Статті в журналах: "Crystalline Silicon (C-Si)"

1

Hafdi, Zoubeida. "Electrical and Optical Characterization of Non-Hydrogenated a-Si/c-Si Heterojunction Solar Cells." Journal of Renewable Energies 24, no. 2 (December 31, 2021): 202–13. http://dx.doi.org/10.54966/jreen.v24i2.981.

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This work deals with the performance of a heterojunction with intrinsic thin layer solar cell by sputtering silicon on p-type crystalline silicon substrate in argon ambient without hydrogen addition. This first effort was an attempt to use cost-effective means to convert light into electricity and to find fabrication processes which use fewer and cheaper materials for the fabrication of solar cells. Since transport mechanisms of amorphous silicon/crystalline silicon heterojunctions are still under investigation, the aim is to examine the behavior of the fabricated samples under electrical and optical constraints. Initial cell characterization includes electrical behavior via current-voltage characteristics and optical investigation via reflectance and absorptance measurements. Results are analyzed in a tentative to follow the absorption, generation and collection processes in the fabricated cell. The heterojunction interface is found to be a limiting factor in the cell performance. Under sun illumination, the open circuit voltage was 140 mV, the short circuit current was of 6 µA and the fill factor was of 42.56 %. Dark current-voltage characteristics indicated a tunneling and/or recombination carrier transport mechanism, while aborptance/reflectance measurements showed a generation process occurring in most in the crystalline silicon-side of the amorphous/crystalline silicon heterojunction. A carrier collection limitation is a very probable origin of the decreased cell generated current.

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2

Agbo, Solomon, Pavol Sutta, Pavel Calta, Rana Biswas, and Bicai Pan. "Crystallized silicon nanostructures — experimental characterization and atomistic simulations." Canadian Journal of Physics 92, no. 7/8 (July 2014): 783–88. http://dx.doi.org/10.1139/cjp-2013-0442.

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We have synthesized silicon nanocrystalline structures from thermal annealing of thin film amorphous silicon-based multilayers. The annealing procedure that was carried out in vacuum at temperatures up to 1100 °C is integrated in a X-ray diffraction (XRD) setup for real-time monitoring of the formation phases of the nanostructures. The microstructure of the crystallized films is investigated through experimental measurements combined with atomistic simulations of realistic nanocrystalline silicon (nc-Si) models. The multilayers consisting of uniformly alternating thicknesses of hydrogenated amorphous silicon and silicon oxide (SiO2) were deposited by plasma enhanced chemical vapor deposition on crystalline silicon and Corning glass substrates. The crystallized structure consisting of nc-Si structures embedded in an amorphous matrix were further characterized through XRD, Raman spectroscopy, and Fourier transform infrared measurements. We are able to show the different stages of nanostructure formation and how the sizes and the crystallized mass fraction can be controlled in our experimental synthesis. The crystallized silicon structures with large crystalline filling fractions exceeding 50% have been simulated with a robust classical molecular dynamics technique. The crystalline filling fractions and structural order of nc-Si obtained from this simulation are compared with our Raman and XRD measurements.

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3

Batstone, J. L. "In situ crystallization of amorphous silicon." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 2 (August 1992): 1346–47. http://dx.doi.org/10.1017/s042482010013136x.

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The solid state transformation of amorphous silicon (a-Si) to crystalline silicon (c-Si) is a first order phase transformation which is driven by the difference in free energy between the amorphous and crystalline phases. The crystallization occurs at temperatures of 500-700°C which are readily accessible with commercial specimen heating stages for the transmission electron microscope (TEM). In this paper we study the a-c phase transformation dynamically by utilizing the powerful technique of in-situ TEM to monitor the nucleation and growth kinetics of thin films of Si. The propagation of a moving a-c interface is presented and an activation energy for crystal growth is obtained.400Å of a-Si was prepared by electron beam deposition of Si at room temperature on amorphous Si3,N4 “window” substrates which required no additional sample preparation for TEM. The samples were examined in a plan view orientation to minimize surface effects on the crystallization process. The a-Si films were annealed by in-situ heating in a Gatan single-tilt hot stage which has a temperature accuracy of ±25°C. Crystallization occurred at ∼700°C with the formation of small crystallites which grew to consume the entire amorphous film. Fig. 1 shows a partially transformed region of a-Si after annealing at 710°C for 6 mins.

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4

Pamungkas, Mauludi Ariesto, and Rendra Widiyatmoko. "Effect of Hydrogenation Temperature on Distribution of Hydrogen Atoms in c-Si and a-Si: Molecular Dynamic Simulations." Key Engineering Materials 706 (August 2016): 55–59. http://dx.doi.org/10.4028/www.scientific.net/kem.706.55.

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Crystalline silicon and amorphous silicon are main materials of solar cell. Under prolonged exposure to light, silicon will degrade in quality. Hydrogenation is believed can minimize this degradation by reduce the number of dangling bond. These Molecular dynamics simulations are aimed to elaborate the hydrogenation process of crystalline silicon and amorphous silicon and to elucidate effect of temperature on distribution of hydrogen atoms. Reactive Force Field is selected owing to its capability to describe forming and breaking of atomic bonds as well as charge transfer. Hydrogenation is performed at 300 K, 600 K, 900 K, and 1200 K. Hydrogenated silicon surface hinders further hydrogen atoms to be absorbed such that not all deposited Hydrogen atoms are absorbed by silicon surface. Generally, the higher hydrogenation temperature the more hydrogen atoms are absorbed. Increment of temperature from 900 K to 1200 K only enhances a few numbers of absorbed hydrogen atoms. However, it can enable hydrogen atoms to penetrate into deeper silicon substrate. It is also observed that hydrogen atoms can penetrate into amorphous silicon deeper than into crystalline silicon.

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5

Wang, Ying Lian, and Jun Yao Ye. "Review and Development of Crystalline Silicon Solar Cell with Intelligent Materials." Advanced Materials Research 321 (August 2011): 196–99. http://dx.doi.org/10.4028/www.scientific.net/amr.321.196.

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The application of solar cell has offered human society renewable clean energy. As intelligent materials, crystalline silicon solar cells occupy absolutely dominant position in photovoltaic market, and this position will not change for a long time in the future. Thereby increasing the efficiency of crystalline silicon solar cells, reducing production costs and making crystalline silicon solar cells competitive with conventional energy sources become the subject of today's PV market. The working theory of solar cell was introduced. The developing progress and the future development of mono-crystalline silicon (c-Si), poly-crystalline silicon (p-Si) and amorphous silicon (a-Si) solar cell have also been introduced.

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6

Holla, M., Tzanimir Arguirov, Winfried Seifert, and Martin Kittler. "Analysis of Silicon Carbide and Silicon Nitride Precipitates in Block Cast Multicrystalline Silicon." Solid State Phenomena 156-158 (October 2009): 41–48. http://dx.doi.org/10.4028/www.scientific.net/ssp.156-158.41.

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We report on the optical and mechanical properties of Si3N4 inclusions, formed in the upper part of mc-Si blocks during the crystallization process. Those inclusions usually appear as crystalline hexagonal tubes or rods. Here we show that in many cases the Si3N4 inclusions contain crystalline Si in their core. The presence of the Si phase in the centre was proven by means of cathodoluminescence spectroscopy and imaging, electron beam induced current measurements and Raman spectroscopy. The crystalline Si3N4 phase was identified as β-Si3N4. Residual stress was revealed at the particles. While the stress is compressive in the Si material surrounding the Si3N4 particles tensile stress is found in the Si core. We assume that the stress is formed during cool down of the Si block and is a consequence of the larger thermal expansion coefficient of Si in comparison to that of β-Si3N4. Iron assisted nitridation of Si at temperatures below 1400 °C is considered a possible mechanism of Si3N4 formation.

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7

Middya, A. R., and Kartik Ghosh. "Quasicrystalline Phase of Silicon on Glass." MRS Proceedings 1493 (2013): 169–74. http://dx.doi.org/10.1557/opl.2013.225.

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ABSTRACTIn this paper, we report new phase of crystalline silicon, quasicrystalline silicon thin-film on glass substrate. The surface topography of these films reveal simultaneous existence of sixfold and fivefold symmetry. We found an array of quasi-unit cell in 2-D that formed quasicrystalline solid. This is first time demonstration of quasicrystalline for single element, silicon (Si). Raman spectra suggests that we found crystalline silicon structure on glass substrate that is not single-crystal silicon (c-Si) but very close to c-Si.

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8

Ech-chamikh, E., A. Essafti, M. Azizan, F. Debbagh, and Y. Ijdiyaou. "Annealing Effects on RF Sputter Deposited a-Si/a-C Multilayers." Journal of Nano Research 4 (January 2009): 103–6. http://dx.doi.org/10.4028/www.scientific.net/jnanor.4.103.

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Amorphous silicon on amorphous carbon (a-Si/a-C) multilayers was deposited by RadioFrequency (RF) sputtering. These multilayers were obtained by alternate deposition of a-C and a-Si layers, respectively from graphite and silicon targets of high purity, on crystalline silicon substrates. The RF power and the argon pressure, during the pulverization, were maintained respectively at 250W and 10-2 mbar. The annealing effects, at temperatures of 450°C and 750°C, on the deposited structures were investigated by X-ray reflectometry. The a-Si/a-C interfaces are abrupt before and after annealing at 450°C. The annealing at 750°C leads to a net decrease of both the upper a-Si layer thickness and the total multilayer thickness with a net enhancement of the interfaces reactivity. The upper silicon layer is crystallized after annealing at 750°C.

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9

Zhang, Junling, Shimou Chen, Haitao Zhang, Suojiang Zhang, Xue Yao, and Zhaohui Shi. "Electrodeposition of crystalline silicon directly from silicon tetrachloride in ionic liquid at low temperature." RSC Advances 6, no. 15 (2016): 12061–67. http://dx.doi.org/10.1039/c5ra23085c.

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Crystalline silicon was fabricated directly from silicon tetrachloride in ionic liquid at low temperature of 100 °C. SEM, TEM and SEAD revealed that as-deposited crystalline Si with diamond cubic crystal structure.

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10

Moreno, Mario, Arturo Ponce, Arturo Galindo, Eduardo Ortega, Alfredo Morales, Javier Flores, Roberto Ambrosio, et al. "Comparative Study on the Quality of Microcrystalline and Epitaxial Silicon Films Produced by PECVD Using Identical SiF4 Based Process Conditions." Materials 14, no. 22 (November 17, 2021): 6947. http://dx.doi.org/10.3390/ma14226947.

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Hydrogenated microcrystalline silicon (µc-Si:H) and epitaxial silicon (epi-Si) films have been produced from SiF4, H2 and Ar mixtures by plasma enhanced chemical vapor deposition (PECVD) at 200 °C. Here, both films were produced using identical deposition conditions, to determine if the conditions for producing µc-Si with the largest crystalline fraction (XC), will also result in epi-Si films that encompass the best quality and largest crystalline silicon (c-Si) fraction. Both characteristics are of importance for the development of thin film transistors (TFTs), thin film solar cells and novel 3D devices since epi-Si films can be grown or etched in a selective manner. Therefore, we have distinguished that the H2/SiF4 ratio affects the XC of µc-Si, the c-Si fraction in epi-Si films, and the structure of the epi-Si/c-Si interface. Raman and UV-Vis ellipsometry were used to evaluate the crystalline volume fraction (Xc) and composition of the deposited layers, while the structure of the films were inspected by high resolution transmission electron microscopy (HRTEM). Notably, the conditions for producing µc-Si with the largest XC are different in comparison to the fabrication conditions of epi-Si films with the best quality and largest c-Si fraction.

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11

Lin, Jian, Hongsub Jee, Jangwon Yoo, Junsin Yi, Chaehwan Jeong, and Jaehyeong Lee. "Surface Passivation of Crystalline Silicon Wafer Using H2S Gas." Applied Sciences 11, no. 8 (April 15, 2021): 3527. http://dx.doi.org/10.3390/app11083527.

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We report the effects of H2S passivation on the effective minority carrier lifetime of crystalline silicon (c-Si) wafers. c-Si wafers were thermally annealed under an H2S atmosphere at various temperatures. The initial minority carrier lifetime (6.97 μs) of a c-Si wafer without any passivation treatments was also measured for comparison. The highest minority carrier lifetime gain of 2030% was observed at an annealing temperature of 600 °C. The X-ray photoelectron spectroscopy analysis revealed that S atoms were bonded to Si atoms after H2S annealing treatment. This indicates that the increase in minority carrier lifetime originating from the effect of sulfur passivation on the silicon wafer surface involves dangling bonds.

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12

Zheng, Zhen, Junyang An, Ruiling Gong, Yuheng Zeng, Jichun Ye, Linwei Yu, Ileana Florea, Pere Roca i Cabarrocas, and Wanghua Chen. "Coupled Investigation of Contact Potential and Microstructure Evolution of Ultra-Thin AlOx for Crystalline Si Passivation." Nanomaterials 11, no. 7 (July 12, 2021): 1803. http://dx.doi.org/10.3390/nano11071803.

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In this work, we report the same trends for the contact potential difference measured by Kelvin probe force microscopy and the effective carrier lifetime on crystalline silicon (c-Si) wafers passivated by AlOx layers of different thicknesses and submitted to annealing under various conditions. The changes in contact potential difference values and in the effective carrier lifetimes of the wafers are discussed in view of structural changes of the c-Si/SiO2/AlOx interface thanks to high resolution transmission electron microscopy. Indeed, we observed the presence of a crystalline silicon oxide interfacial layer in as-deposited (200 °C) AlOx, and a phase transformation from crystalline to amorphous silicon oxide when they were annealed in vacuum at 300 °C.

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13

KIEBACH, RAGNAR, ZHENRUI YU, MARIANO ACEVES-MIJARES, DONGCAI BIAN, and JINHUI DU. "THE DEPOSITION AND CONTROL OF SELF ASSEMBLED SILICON NANO ISLANDS ON CRYSTALLINE SILICON." International Journal of High Speed Electronics and Systems 18, no. 04 (December 2008): 901–10. http://dx.doi.org/10.1142/s0129156408005862.

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The formation of nano sized Si structures during the annealing of silicon rich oxide (SRO) films was investigated. These films were synthesized by low pressure chemical vapor deposition (LPCVD) and used as precursors, a post-deposition thermal annealing leads to the formation of Si nano crystals in the SiO 2 matrix and Si nano islands ( Si nI ) at c-Si /SRO interface. The influences of the excess Si concentration, the incorporation of N in the SRO precursors, and the presence of a Si concentration gradient on the Si nI formation were studied. Additionally the influence of pre-deposition substrate surface treatments on the island formation was investigated. Therefore, the substrate surface was mechanical scratched, producing high density of net-like scratches on the surface. Scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) were used to characterize the synthesized nano islands. Results show that above mentioned parameters have significant influences on the Si nIs . High density nanosized Si islands can epitaxially grow from the c-Si substrate. The reported method is very simple and completely compatible with Si integrated circuit technology.

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14

Nussupov, K. Kh, N. B. Beisenkhanov, S. A. Kukushkin, A. T. Sultanov, S. Keiinbay, D. S. Shynybayev, and A. Zh Kusainova. "FORMATION OF CRYSTALLINE SiC IN NEAR-SURFACE SILICON LAYERS BY METHOD OF COORDINATED SUBSTITUTION OF ATOMS." Herald of the Kazakh-British technical university 20, no. 2 (July 1, 2023): 27–35. http://dx.doi.org/10.55452/1998-6688-2023-20-2-27-35.

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In this work, monocrystalline films of silicon carbide were synthesized on the surface of a Si(100) silicon wafer using the method of coordinated substitution of atoms. The films were synthesized at temperatures of 1200 °C and 1300 °C for 20 minutes in a CO gas flow at a pressure of 0.8 Pa. The effect of 1200–1300 °C temperatures on the formation of single- and polycrystalline layers, as well as nanostructured SiC phases in the near-surface region of silicon by the method of atom substitution, is analyzed. The formation of a high-quality crystalline silicon carbide film and the influence of synthesis conditions on the total volume of SiC structural phases, microstructure and nanostructure of the surface are shown. It was found that an increase in temperature from 1200 °C to 1300 °C led to a more intensive formation of silicon carbide and an increase in the number of Si–C bonds by 1.9 times due to an increase in the thickness of the synthesized silicon carbide layer. There is an increase in the proportion of the crystalline phase due to a more intense transformation of the nuclei of nanocrystals into micro- and nanocrystals. Intense processes of penetration of carbon atoms deep into silicon at a temperature of 1300 °C with amorphization of its structure and the formation of Si-C, which can transform into crystalline phases at temperatures above 1300 °C, are assumed. The proportion of the SiC crystalline phase increases to 50.2% of the film volume due to the intensive transformation of nanocrystal nuclei into micro- and nanocrystals. It has been experimentally shown that the formation of various SiC structures on Si (100) occurs in full accordance with the main principles of the method of coordinated substitution of atoms.

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15

Haberl, Bianca, Malcolm Guthrie, David J. Sprouster, Jim S. Williams, and Jodie E. Bradby. "New insight into pressure-induced phase transitions of amorphous silicon: the role of impurities." Journal of Applied Crystallography 46, no. 3 (May 15, 2013): 758–68. http://dx.doi.org/10.1107/s0021889813010509.

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The pressure-induced phase transformations of a form of amorphous silicon (a-Si) with well characterized impurity levels and structure are examined at pressures up to 40 GPa usingin situsynchrotron X-ray radiation. At ∼12 GPa crystallization commences, but it is not completed until ∼16 GPa. At higher pressures, not all the crystalline phases observed for crystalline silicon (c-Si) appear. On pressure release, none of the metastable crystalline phases observed for c-Si nucleate. Instead an amorphous phase is re-formed. This is in contrast to all previous diamond-anvil studies on a-Si. If full pressure-induced crystallization occurred, the material remained crystalline on unloading. The formation of a-Si upon unloading was only observed when a high-density amorphous phase was reported on loading. The fully characterized nature of the a-Si used in this current study allows for the interpretation of this significant diversity in terms of impurity content of the a-Si used. Namely, this suggests that `ideal' (pure, voidless, structurally relaxed) a-Si will follow the same transition pathway as observed for c-Si, while crystallization of a-Si forms with a high impurity content is retarded or even inhibited. The a-Si used here straddles both regimes and thus, although full crystallization occurs, the more complex crystalline structures fail to nucleate.

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16

Pakhuruddin, Mohd Zamir. "Ray Tracing of Light Trapping Schemes in Thin Crystalline Silicon for Photovoltaics." Solid State Phenomena 301 (March 2020): 183–91. http://dx.doi.org/10.4028/www.scientific.net/ssp.301.183.

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Thin crystalline silicon (c-Si) suffers from poor light absorption which hinders generation of high photocurrent in photovoltaic (PV) devices. To overcome this issue, efficient light trapping (LT) schemes need to be incorporated into the thin c-Si absorber. This paper presents ray tracing of LT schemes in thin c-Si to enhance broadband light absorption within 300-1200 nm wavelength region. For the ray tracing, mono c-Si wafer with 100 μm thickness is investigated and solar spectrum (AM1.5G) at normal incidence is used. Front and rear pyramid textures, silicon nitride (SiNx) anti-reflective coating (ARC) and back surface reflector (BSR) are the LT schemes being studied in this work. With incremental LT schemes, optical properties of the thin c-Si are analyzed. From the absorption curve, maximum potential photocurrent density (Jmax) is calculated, assuming unity carrier collection. The c-Si reference (without LT) exhibits Jmax of 24.93 mA/cm2. With incorporation of incremental LT schemes into the thin c-Si, the Jmax increases, owing to enhanced light coupling and light scattering in the c-Si absorber. The Jmax up to 42.12 mA/cm2 is achieved when all the LT schemes are incorporated into the thin c-Si absorber. This represents 69% enhancement when compared to the Jmax of the c-Si reference.

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17

Follstaedt, D. M., J. A. Knapp, and S. M. Myers. "Mechanical properties of ion-implanted amorphous silicon." Journal of Materials Research 19, no. 1 (January 2004): 338–46. http://dx.doi.org/10.1557/jmr.2004.19.1.338.

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We used nanoindentation coupled with finite element modeling to determine the mechanical properties of amorphous Si layers formed by self-ion implantation of crystalline Si at approximately 100 K. When the effects of the harder substrate on the response of the layers to indentation were accounted for, the amorphous phase was found to have a Young’s modulus of 136 ± 9 GPa and a hardness of 10.9 ± 0.9 GPa, which were 19% and 10% lower than the corresponding values for crystalline Si. The hardness agrees well with the pressure known to induce a phase transition in amorphous Si to the denser β–Sn-type structure of Si. This transition controls the yielding of amorphous Si under compressive stress during indentation, just as it does in crystalline Si. After annealing 1 h at 500 °C to relax the amorphous structure, the corresponding values increase slightly to 146 ± 9 GPa and 11.6 ± 1.0 GPa. Because hardness and elastic modulus are only moderately reduced with respect to crystalline Si, amorphous Si may be a useful alternative material for components in Si-based microelectromechanical systems if other improved properties are needed, such as increased fracture toughness.

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18

Fangsuwannarak, Thipwan, K. Amonsurintawong, and Suwat Sopitpan. "Aluminum-Induced Crystallization of p⁺ Silicon Pinholes for the Formation of Rear Passivation Contact in Solar Cell." Key Engineering Materials 547 (April 2013): 31–40. http://dx.doi.org/10.4028/www.scientific.net/kem.547.31.

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Formation of nano-crystalline p+ silicon (Si) in pinholes through a silicon dioxide layer was achieved by pinning of aluminum through the thin silicon dioxide (SiO2) layer. In addition to opening holes of SiO2 layer by aluminum (Al) pining, amorphous silicon (a-Si) was subsequent deposited on the Al layer and another heated at low temperature (500°C) to allow solid- phase epitaxial growth of p+ Si in the pinholes due to the Al induced layer exchange process. The poly-crystalline p+ Si obtains lower effective surface recombination than the Al back surface field (BSF). The technique demonstrated to result in ohmic contacts with low contact resistance. The evaluation of Al-induced crystallization of a-Si in a-Si/Al bilayer was studied by X-ray diffraction. In this paper, the influence of a-Si/Al thickness ratio on the specific conductivity value and crystalline grain size of the p+ Si thin film is discussed. The obtained results are helpful for a further design of the rear passivation contact in solar cell.

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19

Grzonka, Justyna, Ryszard Mania, János L. Lábár, and Jerzy Morgiel. "Effect of Silicon Additions in CrSi (10, 20, 30, 40 at. % Si) Magnetron Targets on Microstructure of Reactively Deposited (Cr,Si)N Coatings." Solid State Phenomena 186 (March 2012): 182–87. http://dx.doi.org/10.4028/www.scientific.net/ssp.186.182.

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The CrSi compacts containing 10, 20, 30 and 40 at. % Si sintered from mixed elemental powders were used as targets for reactively deposited magnetron (Cr,Si)N coatings. The silicon substrates were kept either at ambient temperature or heated up to 600 °C. The microstructure observations were performed using TECNAI FEG (200 kV) with EDAX X-ray Energy Dispersive Spectroscopy (EDS) system and JEOL 3010 (300 kV) with Gatan Energy Filtering (GIF) attachment microscopes. The thin foils were cut using QUANTA Focused Ion Beam (FIB) system. The performed investigations proved that increasing silicon content in coatings deposited at 600 °C using CrSi10, CrSi20 and CrSi30 targets caused a refining of their fully crystalline CrN-type columnar microstructure from ~ 40 to ~ 35 and ~ 25 nm. The deposition performed from the same targets, but at ambient temperatures, i.e. without resistive heating of the substrates, produced coatings of mixed crystalline-amorphous type. They were characterized by gradient microstructure, i.e. amorphous material was prevailing close to the substrate and decreasing close to coating surface. The rising of silicon content in the targets resulted in decreasing amount of crystalline phase. The coatings obtained from Cr40Si target were fully amorphous independently of substrate temperature during deposition. The measurements of local chemical compositions obtained using EDS technique indicated that the Cr:Si ratio in the coatings roughly reproduced that present in the targets used for their deposition. Additionally, these measurements indicated that all coatings are contaminated with oxygen. The mapping of chemical composition using GIF technique of mixed crystalline-amorphous coatings proved that they are enriched in Cr and Si, respectively. The present results showed, that relying on single CrSi target magnetron sputtering the crystalline-amorphous nano-composite could be obtain at silicon additions from 10 to 30 at %, i.e. well above were that type of microstructure is formed during deposition using double target magnetron systems. Additionally, for the first time, the measurements helped to prove that the crystallites and amorphous material are enriched in chromium and silicon respectively, i.e. confirmed presence of CrN/Si3N4 composite.

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20

Wang, Dashan, James J. Tunney, Xiaomei Du, Michael L. Post, and Raynald Gauvin. "Transmission electron microscopy investigation of interfacial reactions between SrFeO3 thin films and silicon substrates." Journal of Materials Research 22, no. 1 (January 2007): 76–88. http://dx.doi.org/10.1557/jmr.2007.0005.

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The SrFeO3/SiO2/Si thin film system has been studied using transmission electron microscopy (TEM). The thin films of SrFeO3 were grown by pulsed laser deposition onto silicon substrates with a SiO2 buffer layer at room temperature (RT) and 700 °C and subjected to annealing for various periods of time at temperature T = 700 °C. Transmission electron microscopy characterization showed that the microstructure of the film deposited at room temperature contained crystalline and amorphous layers. Silicon diffusion into SrFeO3 films occurred at the SiO2 interface for the samples deposited at 700 °C and for those films annealed at 700 °C. The silicon diffusion-induced interfacial reactions resulted in the phase transformations and the growth of complex crystalline and amorphous phases. The principal compositions of these phases were Sr(Fe,Si)12O19, SrOx and amorphous [Sr-Fe-O-Si].

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21

Jia, Xuguang, Ziyun Lin, Terry Chien-Jen Yang, Binesh Puthen-Veettil, Lingfeng Wu, Gavin Conibeer, and and Ivan Perez-Wurfl. "Post-Sputtering Heat Treatments of Molybdenum on Silicon Wafer." Applied Sciences 8, no. 9 (September 18, 2018): 1692. http://dx.doi.org/10.3390/app8091692.

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This paper investigated the property evolutions of Mo thin films that were subjected to post-sputtering heat treatments from 700 °C to 1100 °C. It was found that, after annealing, the use of Si wafers eliminated crack formations found in previously reported Mo thin films sputtered on fused silica substrates. The recrystallization of the Mo thin film was found to start at 900 °C, which led to rearrangements of the preferred crystalline orientation and enhancement of grain size when the annealing temperature was further increased. The electrical conductivity of the Mo thin films was majorly affected by the increase of Mo crystallite size as the annealing temperature was increased. Overall, the improvement of material sustainability and compatibility in the high temperature annealing process has made it positive to implement a Mo-Si contact-substrate scheme for vertical structured Si QDs solar cells.

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22

Chen, Yusi, Yangsen Kang, Jieyang Jia, Yijie Huo, Muyu Xue, Zheng Lyu, Dong Liang, Li Zhao, and James S. Harris. "Nanostructured Dielectric Layer for Ultrathin Crystalline Silicon Solar Cells." International Journal of Photoenergy 2017 (2017): 1–6. http://dx.doi.org/10.1155/2017/7153640.

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Nanostructures have been widely used in solar cells due to their extraordinary photon management properties. However, due to poor pn junction quality and high surface recombination velocity, typical nanostructured solar cells are not efficient compared with the traditional commercial solar cells. Here, we demonstrate a new approach to design, simulate, and fabricate whole-wafer nanostructures on dielectric layer on thin c-Si for solar cell light trapping. The optical simulation results show that the periodic nanostructure arrays on dielectric materials could suppress the reflection loss over a wide spectral range. In addition, by applying the nanostructured dielectric layer on 40 μm thin c-Si, the reflection loss is suppressed to below 5% over a wide spectra and angular range. Moreover, a c-Si solar cell with 2.9 μm ultrathin absorber layer demonstrates 32% improvement in short circuit current and 44% relative improvement in energy conversion efficiency. Our results suggest that nanostructured dielectric layer has the potential to significantly improve solar cell performance and avoid typical problems of defects and surface recombination for nanostructured solar cells, thus providing a new pathway towards realizing high-efficiency and low-cost c-Si solar cells.

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23

Ding, K., U. Aeberhard, A. Lambertz, V. Smirnov, B. Holländer, F. Finger, and U. Rau. "Impact of doped microcrystalline silicon oxide layers on crystalline silicon surface passivation." Canadian Journal of Physics 92, no. 7/8 (July 2014): 758–62. http://dx.doi.org/10.1139/cjp-2013-0627.

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This paper reports on a comparative study of the impact of phosphorous and boron doped microcrystalline silicon oxide (μc-SiOx:H) layers on the surface passivation of n- and p-type doped crystalline silicon float zone wafers in correlation with the material properties of the μc-SiOx:H layers. The poor surface passivation of μc-SiOx:H films deposited directly on c-Si surface might be attributed to the incorporation of doping impurities, the surface damaging by ion bombardment and (or) the low amount of hydrogen at the μc-SiOx:H/c-Si interface. The different impact of n- and p-type doped μc-SiOx:H films on the passivation of n- and p-type doped wafers with and without an additional a-SiOx:H passivation layer are correlated to the differences in the strength of the field effect at the heterojunction and to the presence of boron atoms that can cause the rupture of Si–H bonds.

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24

Jin, Jing, Xiao Lei Qu, and Wei Min Shi. "Two-Step Annealing for Solution-Based Metal Induced Crystallization of Amorphous Silicon Films." Advanced Materials Research 1052 (October 2014): 109–14. http://dx.doi.org/10.4028/www.scientific.net/amr.1052.109.

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Solution-based nickel (Ni)-induced crystallization (S-MIC) of amorphous silicon (a-Si) films has been studied with a two-step annealing process. We especially introduced Ethyl cellulose (EC) into the Ni-salt solution, so the viscous Ni-salt solution can be uniformly spin-coated on the a-Si film prepared by plasma enhanced chemical vapor deposition (PECVD). The annealing temperature can be first set from room temperature (RT) to 400°C and kept at 400°C for 2 h in nitrogen ambience. And then, it is increased from 500°C to 550°C and kept for several hours in the following annealing. The correlations among crystallization, the concentrations of Ni-salt solution and annealing conditions can be discussed. The experimental results show that with the help of the two-step annealing, the a-Si films can be crystallized at a low temperature of 500°C. The crystalline fraction gets up to 81.2% after annealing at 520°C for 2 h and the grain size of the polycrystalline Si film is approximately 0.2 μm. Energy dispersive spectroscopy (EDS) analysis shows that very little Ni metal atoms reside in the crystallized Si film for S-MIC.

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25

Ponomarev, Ilia, and Peter Kroll. "29Si NMR Chemical Shifts in Crystalline and Amorphous Silicon Nitrides." Materials 11, no. 9 (September 7, 2018): 1646. http://dx.doi.org/10.3390/ma11091646.

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We investigate 29Si nuclear magnetic resonance (NMR) chemical shifts, δiso, of silicon nitride. Our goal is to relate the local structure to the NMR signal and, thus, provide the means to extract more information from the experimental 29Si NMR spectra in this family of compounds. We apply structural modeling and the gauge-included projector augmented wave (GIPAW) method within density functional theory (DFT) calculations. Our models comprise known and hypothetical crystalline Si3N4, as well as amorphous Si3N4 structures. We find good agreement with available experimental 29Si NMR data for tetrahedral Si[4] and octahedral Si[6] in crystalline Si3N4, predict the chemical shift of a trigonal-bipyramidal Si[5] to be about −120 ppm, and quantify the impact of Si-N bond lengths on 29Si δiso. We show through computations that experimental 29Si NMR data indicates that silicon dicarbodiimide, Si(NCN)2 exhibits bent Si-N-C units with angles of about 143° in its structure. A detailed investigation of amorphous silicon nitride shows that an observed peak asymmetry relates to the proximity of a fifth N neighbor in non-bonding distance between 2.5 and 2.8 Å to Si. We reveal the impact of both Si-N(H)-Si bond angle and Si-N bond length on 29Si δiso in hydrogenated silicon nitride structure, silicon diimide Si(NH)2.

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26

Yu, Kaihao, Tao Xu, Xing Wu, Wen Wang, Hui Zhang, Qiubo Zhang, Luping Tang, and Litao Sun. "In Situ Observation of Crystalline Silicon Growth from SiO2 at Atomic Scale." Research 2019 (October 30, 2019): 1–9. http://dx.doi.org/10.34133/2019/3289247.

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The growth of crystalline Si (c-Si) via direct electron beam writing shows promise for fabricating Si nanomaterials due to its ultrahigh resolution. However, to increase the writing speed is a major obstacle, due to the lack of systematic experimental explorations of the growth process and mechanisms. This paper reports a systematic experimental investigation of the beam-induced formation of c-Si nanoparticles (NPs) from amorphous SiO2 under a range of doses and temperatures by in situ transmission electron microscopy at the atomic scale. A three-orders-of-magnitude writing speed-up is identified under 80 keV irradiation at 600°C compared with 300 keV irradiation at room temperature. Detailed analysis reveals that the self-organization of c-Si NPs is driven by reduction of c-Si effective free energy under electron irradiation. This study provides new insights into the formation mechanisms of c-Si NPs during direct electron beam writing and suggests methods to improve the writing speed.

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27

Zhang, Cong, Ling Qu, and Wenjie Yuan. "Effects of Si/C Ratio on the Phase Composition of Si-C-N Powders Synthesized by Carbonitriding." Materials 13, no. 2 (January 12, 2020): 346. http://dx.doi.org/10.3390/ma13020346.

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Si-C-N based materials possess interesting properties such as high hardness and oxidation resistance. The compacts of silicon and cornstarch with different Si/C ratios were subjected to carbonitriding at 1350–1550 °C. Reaction products were characterized by X-ray powder diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscope (TEM). The effects of Si/C ratio on the phase composition of Si-C-N powders were investigated. The results revealed that the Si/C ratio played a crucial role on the formation of crystalline silicon carbonitride (SiCN) and the phase composition of Si-C-N powders. It was demonstrated that liquid silicon is an important medium and reaction site for the introduction of nitrogen, so the Si content in reactants has affected the N content in the product. On the other hand, carbon participates in the carbonization of Si3N4 and the formation of SiC. The contents of C-N bond and SiCN in the products are carbon content-dependent. Combining the above two aspects, the maximum yield of SiCN can be achieved with the Si/C ratio of 1:1 to 1:1.5.

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28

Park, Sang-Hui, Han-Gyeol Lee, Jin-Hoon Ju, Sang-Hee Park, Gyu-Bong Cho, and Ki-Won Kim. "Electrochemical Properties of Silicon-Polyacrylonitrile (PAN) Composite Anodes for Flexible Batteries." Journal of Nanoscience and Nanotechnology 20, no. 11 (November 1, 2020): 7039–44. http://dx.doi.org/10.1166/jnn.2020.18831.

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Polyacrylonitrile (PAN)/Si composite fibers (electrodes) with flexibility were fabricated using an elec-trospinning method and then Si-embedded carbon (Si/C) fibers were prepared by carbonizing the composite fibers at 800, 900, and 1000°C. Si particles were distributed in the interior and exterior of entangled PAN fibers. After carbonization, the structure of electrodes was preserved but the diameter of fibers was decreased owing to the release of component elements constituting PAN such as nitrogen and oxygen. Crystalline Si particles existed in carbon fibers with both amorphous and crystalline phases. As carbonization temperature increased, the carbon content and the crys-tallinity of carbon increased. The electrode carbonized at 1000°C with the lowest charge transfer resistance exhibited the best electrochemical properties in terms of capacity, coulombic efficiency and cycle life.

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29

Krajangsang, Taweewat, Apichan Moollakorn, Sorapong Inthisang, Amornrat Limmanee, Kobsak Sriprapha, Nattaphong Boriraksantikul, Tianchai Taratiwat, Nirod Akarapanjavit, and Jaran Sritharathikhun. "Study of an Amorphous Silicon Oxide Buffer Layer for p-Type Microcrystalline Silicon Oxide/n-Type Crystalline Silicon Heterojunction Solar Cells and Their Temperature Dependence." International Journal of Photoenergy 2014 (2014): 1–5. http://dx.doi.org/10.1155/2014/251508.

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Intrinsic hydrogenated amorphous silicon oxide (i-a-SiO:H) films were used as front and rear buffer layers in crystalline silicon heterojunction (c-Si-HJ) solar cells. The surface passivity and effective lifetime of these i-a-SiO:H films on an n-type silicon wafer were improved by increasing the CO2/SiH4ratios in the films. Using i-a-SiO:H as the front and rear buffer layers in c-Si-HJ solar cells was investigated. The front i-a-SiO:H buffer layer thickness and the CO2/SiH4ratio influenced the open-circuit voltage(Voc), fill factor (FF), and temperature coefficient (TC) of the c-Si-HJ solar cells. The highest total area efficiency obtained was 18.5%(Voc=700 mV,Jsc=33.5 mA/cm2, andFF=0.79). The TC normalized for this c-Si-HJ solar cell efficiency was −0.301%/°C.

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30

Shahriar, Ahnaf, Saif Hasnath, and Md Aminul Islam. "Effects of Operating Temperature on the Performance of c-Si, a-Si:H, CIGS, and CdTe/CdS Based Solar Cells." EDU Journal of Computer and Electrical Engineering 1, no. 1 (August 20, 2020): 31–37. http://dx.doi.org/10.46603/ejcee.v1i1.21.

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Solar photovoltaic technology is one of the most promising, economical and green technologies to harvest energy with the least effect on the environment. Crystalline silicon (c-Si), amorphous silicon (a-Si), CIGS, CdTe/CdS etc., are dominating the PV market. Operating temperature plays an important role in the performance of solar cells. A comparative investigation on the effect of operating temperature on the market available solar cells is very important in choosing the better PV technology in high-temperature applications. In this study, the performances of different solar cell technologies, namely crystalline silicon (c-Si), amorphous silicon (a-Si), CIGS, and CdTe/CdS based solar cells, have been investigated under different operating temperature by using SCAPS-1D simulation software. All parameter of a solar cell for different technology has been studied under the varying operation temperature ranging from 25 ºC to 70 ºC and the rate of change of them has been recorded. It has been found that the Voc and Pmax degrade significantly and Isc increases slightly with an increase in temperature. The temperature coefficients of Pmax for c-Si, a-Si, CdTe and CIGS have been found as -0.0724/K, -0.0362/K, -0.0112/K and -0.0663/K, respectively. On the other hand, c-Si and CIGS technologies show better quantum efficiency behaviour in both room and high operating temperatures.

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31

PENG, YINQIAO, JICHENG ZHOU, JIEHONG GONG, QINRONG YU, and GUIBIN LEI. "MICROSTRUCTURE AND DIELECTRIC PROPERTIES OF SILICON CARBONITRIDE DIELECTRIC BARRIER FILMS DEPOSITED BY SPUTTERING." Surface Review and Letters 25, no. 03 (March 8, 2018): 1850065. http://dx.doi.org/10.1142/s0218625x18500658.

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Silicon carbon nitride (SiCN) films were prepared on silicon substrate by reactive magnetron sputtering of a sintered silicon carbide target in a mixture of argon, nitrogen and acetylene. Detailed studies including energy dispersive spectrometer, atomic force microscope, X-ray diffraction, Fourier transformed infrared spectrometry and [Formula: see text]–[Formula: see text] measuring instrument were performed. The as-deposited SiCN films do not exhibit obvious crystalline phase, and the SiCN films annealed at 600[Formula: see text]C show SiC crystal and graphite carbon. The SiCN films mainly consist of Si–N, Si–C, Si–O, C–C, C[Formula: see text]N, Si–Hn and N–Hn bonds, and increasing C2H2 flow rate promotes the formation of C–C, N–Hn and Si–N bonds. The SiCN film with low dielectric constant of 3.8 and compact structure was successfully prepared.

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32

Nikolskaia, A. B., S. S. Kozlov, M. F. Vildanova, O. K. Karyagina, and O. I. Shevaleevskiy. "Four-terminal perovskite-silicon tandem solar cells for low light applications." Journal of Physics: Conference Series 2103, no. 1 (November 1, 2021): 012191. http://dx.doi.org/10.1088/1742-6596/2103/1/012191.

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Abstract Here novel high efficient semi-transparent perovskite solar cells (PSCs) based on ZrO2 photoelectrodes were fabricated and were used as top elements in tandem systems with crystalline silicon (c-Si) solar cells in four-terminal configuration. The comparative analysis of photovoltaic parameters measured for PSCs, c-Si solar cells and PSC/c-Si tandem solar cells demonstrated that the use of ZrO2 photoelectrodes allows to improve the PSC performance and to achieve efficiencies for PSC/c-Si tandem solar cell higher than for a standalone c-Si solar cell under varying illumination conditions.

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33

Perný, Milan, Vladimír Šály, František Janíček, Miroslav Mikolášek, Michal Váry, and Jozef Huran. "Electric measurements of PV heterojunction structures a-SiC/c-Si." Journal of Electrical Engineering 69, no. 1 (January 1, 2018): 52–57. http://dx.doi.org/10.1515/jee-2018-0007.

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Abstract Due to the particular advantages of amorphous silicon or its alloys with carbon in comparison to conventional crystalline materials makes such a material still interesting for study. The amorphous silicon carbide may be used in a number of micro-mechanical and micro-electronics applications and also for photovoltaic energy conversion devices. Boron doped thin layers of amorphous silicon carbide, presented in this paper, were prepared due to the optimization process for preparation of heterojunction solar cell structure. DC and AC measurement and subsequent evaluation were carried out in order to comprehensively assess the electrical transport processes in the prepared a-SiC/c-Si structures. We have investigated the influence of methane content in deposition gas mixture and different electrode configuration.

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34

NAKHMANSON, S. M., N. MOUSSEAU, G. T. BARKEMA, P. M. VOYLES, and D. A. DRABOLD. "MODELS OF PARACRYSTALLINE SILICON WITH A DEFECT-FREE BANDGAP." International Journal of Modern Physics B 15, no. 24n25 (October 10, 2001): 3253–57. http://dx.doi.org/10.1142/s0217979201007580.

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Recently there have been attempts to create physically realistic models for para/poly-crystalline silicon (containing randomly oriented c-Si grains embedded in a disordered matrix) by means of empirical molecular dynamics. These models demonstrate acceptable geometrical and vibrational properties but fail to reproduce the correct electronic bandgap due to the presence of numerous "frozen-in" coordination defects. We propose a new procedure for the preparation of more realistic models of paracrystalline silicon based on a modification of the bond-switching method of Wooten, Winer and Weaire. Our new method allows us to create interfaces between the crystalline and disordered phases of Si with no coordination defects. Models with 400, 1000, and 4000 atoms were constructed. All the models have ~10 atomic % of the crystalline phase. The two smaller models contain a single crystalline grain and the largest model contains 4 randomly oriented grains. Our models show good geometrical and vibrational properties compared to good continuous random networks models of a-Si and also display excellent optical properties, correctly reproducing the electronic bandgap of amorphous silicon.

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35

Justo, João F., Cesar R. S. da Silva, I. Pereyra, and Lucy V. C. Assali. "Structural and Electronic Properties of Si_1-xC_xO₂." Materials Science Forum 483-485 (May 2005): 577–80. http://dx.doi.org/10.4028/www.scientific.net/msf.483-485.577.

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There is growing interest in understanding the properties of SiC-SiO2 interfaces, which can be formed by oxidation of silicon carbide surfaces. Here, we used variable cell shape ab initio molecular dynamics to investigate the structural and electronic properties of crystalline phases of silicon oxycarbide which could appear within such interfaces. We find that carbonoxygen single bonds may remain stable inside a silicon oxide matrix. For the Si2CO6 compound, there are at least two crystalline phases, both having large bulk modulii and wide bandgaps.

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36

Abdulkadir, Auwal, Azlan Abdul Aziz, and Mohd Zamir Pakhuruddin. "Properties of PEDOT:PSS on Black Silicon and Hybrid Textured Surfaces." Solid State Phenomena 336 (August 30, 2022): 109–17. http://dx.doi.org/10.4028/p-5o4tp7.

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This work investigates properties of Poly (3,4-ethylenedioxythiophene)–poly (styrene sulfonate) (PEDOT:PSS) on black silicon (nanotextured) and hybrid textured (nanotextured/microtextured) surfaces. The black silicon (b-Si) surface is fabricated using two-step metal-assisted chemical etching (MACE) process on crystalline silicon (c-Si) while the hybrid textures are fabricated using two-step MACE process on microscale pyramids. With PEDOT:PSS, weighted average reflection (WAR) reduces from 9.2% to 7.7% for b-Si and from 7.2% to 5.2% for hybrid textures. This is due to the anti-reflective (AR) property of the polymer. Electrical characterizations of the PEDOT:PSS layer reveal higher sheet resistance (Rs), lower hole concentration (nh) and improved mobility (μh) with the presence of the surface textures on c-Si, in comparison to the results from planar c-Si reference.

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37

Li, Wei, Dong Lin Xia, Ming Xia Song, Zhen Zhong Zhang, Jia Miao Ni, and Xiu Jian Zhao. "Nickel Induced Lateral Crystallization of Amorphous Silicon Film by Electroless Planting." Advanced Materials Research 66 (April 2009): 147–50. http://dx.doi.org/10.4028/www.scientific.net/amr.66.147.

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A novel deposition way of nickel film for crystallization amorphous silicon film is introduced. Electroless nickel planting is a convenient and inexpensive way to deposit nickel without using the electric field or any large facility. A 200 nm nickel film is deposited on the glass substrates and then a 300nm a-Si film is deposited on the nickel film with a horizontal electric field assisted to enhance amorphous silicon crystallization. The bi-layer film is annealed at 500°C for several hours in the nitrogen atmosphere. The crystallized Si thin films were characterized by Raman spectroscopy, Field emission scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The Raman demonstrates that the a-Si has been crystallized. Furthermore the FE-SEM shows the lateral crystalline morphology, the length of grain is up to 5µm and the EDS reveals the nickel distribution in the MILC and MIC area.

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38

Chrostowski, Marta, José Alvarez, Alessia Le Donne, Simona Binetti, and Pere Roca i Cabarrocas. "Annealing of Boron-Doped Hydrogenated Crystalline Silicon Grown at Low Temperature by PECVD." Materials 12, no. 22 (November 19, 2019): 3795. http://dx.doi.org/10.3390/ma12223795.

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We investigate low-temperature (<200 °C) plasma-enhanced chemical vapor deposition (PECVD) for the formation of p–n junctions. Compared to the standard diffusion or implantation processes, silicon growth at low temperature by PECVD ensures a lower thermal budget and a better control of the doping profile. We previously demonstrated the successful growth of boron-doped epitaxial silicon layers (p+ epi-Si) at 180 °C. In this paper, we study the activation of boron during annealing via dark conductivity measurements of p+ epi-Si layers grown on silicon-on-insulator (SOI) substrates. Secondary Ion Mass Spectroscopy (SIMS) profiles of the samples, carried out to analyze the elemental composition of the p+ epi-Si layers, showed a high concentration of impurities. Finally, we have characterized the p+ epi-Si layers by low-temperature photoluminescence (PL). Results revealed the presence of a broad defect band around 0.9 eV. In addition, we observed an evolution of the PL spectrum of the sample annealed at 200 °C, suggesting that additional defects might appear upon annealing.

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39

Lu, You Jun, Hong Fang Shen, and Sheng Wei Guo. "Microwave Synthesis of Silicon Carbide Nano Powders with Silicon and Carbon." Key Engineering Materials 602-603 (March 2014): 118–21. http://dx.doi.org/10.4028/www.scientific.net/kem.602-603.118.

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Nanosized silicon carbide powders were synthesized from a mixture of silicon and carbon by microwave heating methods. The Result Indicates SiC can be formed at lower temperatures by using the Si-C reaction at 1200°C for 30min. XRD patterns shows that SiC peaks appeared as the only crystalline phase. SEM photo shows the particle size was 100～200 nanometer. At the same time, Effects of chemical reaction of silicon and carbon was researched by mechanical activated microwave synthesis.

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40

Gerardi, Gary J., Edward H. Poindexter, and David J. Keeble. "Paramagnetic Centers and Dopant Excitation in Crystalline Silicon Carbide." Applied Spectroscopy 50, no. 11 (November 1996): 1428–34. http://dx.doi.org/10.1366/0003702963904755.

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Impurities, point defects, and dopant excitation in SiC have been examined by electron paramagnetic resonance (EPR). The pervasive nitrogen n-type dopant was found to show a substantial photo-enhancement, not due to generation of carrier pairs. Aluminum in Al-doped SiC showed a strong EPR signal below 4 K, which disappeared as the sample was warmed to 10 K, because of the onset of impurity band conduction. The Al EPR signal intensity depends on the degree of compensation. Boron EPR appeared in samples where excess Al counteracts the compensation of B ions by N dopant. Hydrogen plasma anneal at 250 °C partially passivated Al; however, extended heating in vacuum, expected to depassivate, actually further decreased the Al signal. Abrasion damage produced a featureless, isotropic signal suggestive of the bulk damage signal in Si, indicating dangling C or Si orbitals. An oxide interface signal, in analogy to Pb of oxidized Si, was not isolated; the observed signal included a damage-like line.

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41

Gedvilas, L. M., and A. H. Mahan. "Identification of Possible Bonding Sites for Post Deposition Oxygen Absorption in Microcrystalline Silicon." MRS Proceedings 808 (2004). http://dx.doi.org/10.1557/proc-808-a9.2.

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ABSTRACTUsing infrared (IR) spectroscopy and x-ray diffraction, the nature of the grain boundaries in twom c-Si films deposited by hot wire CVD, displaying similar crystalline volume fractionsbut very different behavior upon exposure to atmospheric contaminants, is analyzed. For the film exhibiting significant post deposition oxidation, the IR spectrum in the 2100 cm−1 Si-H stretch mode region contains two sharp and very narrow peaks, suggesting that the crystallites have been incorporated into them c-Si films with their hydrogenated surfaces relatively intact.By comparing these peak frequencies to those in the literature for Si-H bonding on c-Si surfaces, we identify certain crystallite orientations which, when comprising the c-Si grain boundaries, are particularly susceptible to oxidation. We further suggest that the distribution of H in this grain boundary/crystallite surface region is crucial for depositing c-Si films with good electronic properties and minimal post deposition oxidation.

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42

Aichberger, S. v., O. Hahneiser, J. Löffler, H. Feist, and M. Kunst. "Excess Charge Carrier Kinetics in Amorphous Silicon/Crystalline Silicon Heterojunctions." MRS Proceedings 507 (1998). http://dx.doi.org/10.1557/proc-507-163.

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ABSTRACTBy contactless transient photoconductivity measurements it is shown that i a-Si:H films, both of standard quality films and annealed low temperature films, passivate the c-Si surface for electron-hole pairs generated in the c-Si substrate. Films deposited at low temperature without annealing do not lead to passivation of the c-Si surface. The injection of excess electrons from a standard a-Si:H film into c-Si with a time constant of a few microseconds and a rather high efficiency was observed. For an annealed 120°C a-Si:H film a slower and less efficient injection was measured, whereas an annealed 50°C a-Si:H shows no appreciable injection.

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43

Chu, Feihong, Xianlin Qu, Yongcai He, Wenling Li, Xiaoqing Chen, Zilong Zheng, Miao Yang, et al. "Prediction of sub-pyramid texturing as the next step towards high efficiency silicon heterojunction solar cells." Nature Communications 14, no. 1 (June 16, 2023). http://dx.doi.org/10.1038/s41467-023-39342-3.

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AbstractThe interfacial morphology of crystalline silicon/hydrogenated amorphous silicon (c-Si/a-Si:H) is a key success factor to approach the theoretical efficiency of Si-based solar cells, especially Si heterojunction technology. The unexpected crystalline silicon epitaxial growth and interfacial nanotwins formation remain a challenging issue for silicon heterojunction technology. Here, we design a hybrid interface by tuning pyramid apex-angle to improve c-Si/a-Si:H interfacial morphology in silicon solar cells. The pyramid apex-angle (slightly smaller than 70.53°) consists of hybrid (111)0.9/(011)0.1 c-Si planes, rather than pure (111) planes in conventional texture pyramid. Employing microsecond-long low-temperature (500 K) molecular dynamic simulations, the hybrid (111)/(011) plane prevents from both c-Si epitaxial growth and nanotwin formation. More importantly, given there is not any additional industrial preparation process, the hybrid c-Si plane could improve c-Si/a-Si:H interfacial morphology for a-Si passivated contacts technique, and wide-applied for all silicon-based solar cells as well.

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44

Pearton, S. J. "Hydrogen in Crystalline Silicon." MRS Proceedings 59 (1985). http://dx.doi.org/10.1557/proc-59-457.

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ABSTRACTThe ability of hydrogen to migrate in crystalline Si at low temperatures (<400°C) and bond to a variety of both shallow and deep level impurities, passivating their electrical activity, is of fundamental and technological interest. Recent results on the deactivation of the shallow acceptors in Si are compared with similar experiments in other semiconductors, microscopic models are proposed, and the implications for the states of hydrogen in the Si lattice at a variety of temperatures, and the diffusivity of some of these different states, is discussed. New results on the migration of atomic hydrogen under electronic stimulation are also detailed, along with a compendium of the deep levels in Si passivated by reaction with hydrogen. Surface damage by hydrogen-containing plasmas, and the infrared and electrical properties of H-related defect complexes are also reviewed.

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45

Sohn, Dong Kyun, Dae Gyu Moon, and Byung Tae Ahn. "Copper-Enhanced Solid Phase Crystallization of Amorphous Silicon Films." MRS Proceedings 424 (1996). http://dx.doi.org/10.1557/proc-424-225.

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AbstractLow-temperature crystallization of amorphous Si (a-Si) films was investigated by adsorbing copper ions on the surface of the films. The copper ions were adsorbed by spincoating of Cu solution. This new process lowered the crystallization temperature and reduced crystallization time of a-Si films. For 1000 ppm solution, the a-Si film was partly crystallized down to 500°C in 20 h and almost completely crystallized at 530°C in 20 h. The adsorbed Cu on the surface acted as a seed of crystalline and caused fractal growth. The fractal size was varied from 10 to 200 prm, depending on the Cu concentration in solution. But the grain size of the films was about 400 nm, which was similar to that of intrinsic films crystallized at 600°C.

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46

Farrokh Baroughi, Mahdi, and Siva Sivoththaman. "Interface Study Of Nanocrystalline Silicon and Crystalline Silicon Using Microwave Photoconductivity Decay." MRS Proceedings 910 (2006). http://dx.doi.org/10.1557/proc-0910-a04-04.

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AbstractThis paper presents a measurement technique for studying of the interface between a nanocrystalline silicon (nc-Si) film and a crystalline silicon (c-Si) substrate using microwave photoconductivity decay (MWPCD). The nc-Si films were deposited using plasma enhanced chemical vapor deposition of highly hydrogen-diluted silane. The films were deposited on both sides of the high purity float-zone (FZ) Si wafers. The high resolution transmission electron microscope (HRTEM) analysis of the interface and the characterization of the effective excess carrier lifetime of the samples using MWPCD revealed the following results: (i) The crystallinity of the deposited nc-Si films is very high. The nc-Si film follows the crystal orientation of the substrate such that not a well-defined boundary between nc-Si film and the c-Si substrate is observed. (ii) A surface recombination velocity of less than 10 cm/s was measured for the interface region of the nc-Si/c-Si junctions. (iii) A small discontinuity in the band-energy diagram of the interface region was observed.

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47

Huh, Hwang, and Jung H. Shin. "Formation of Large, Orientation-Controlled, Nearly Single Crystalline Si Thin Films on SiO2 Using Contact Printing of Rolled and Annealed Nickel Tapes." MRS Proceedings 762 (2003). http://dx.doi.org/10.1557/proc-762-a17.13.

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AbstractAmorphous silicon (a-Si) films prepared on oxidized silicon wafer were crystallized to a highly textured form using contact printing of rolled and annealed nickel tapes. Crystallization was achieved by first annealing the a-Si film in contact with patterned Ni tape at 600°C for 20 min in a flowing forming gas (90 % N2, 10 % H2) environment, then removing the Ni tape and further annealing the a-Si film in vacuum for2hrsat600°C. An array of crystalline regions with diameters of up to 20 μm could be formed. Electron microscopy indicates that the regions are essentially single-crystalline except for the presence of twins and/or type A-B formations, and that all regions have the same orientation in all 3 directions even when separated by more than hundreds of microns. High resolution TEM analysis shows that formation of such orientation-controlled, nearly single crystalline regions is due to formation of nearly single crystalline NiSi2 under the point of contact, which then acts as the template for silicide-induced lateral crystallization. Furthermore, the orientation relationship between Si grains and Ni tape is observed to be Si (110) || Ni (001)

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48

Islam, Md N., Sanjay K. Ram, and Satyendra Kumar. "Electronic Transport Across Porous/Crystalline Silicon Heterojunctions." MRS Proceedings 716 (2002). http://dx.doi.org/10.1557/proc-716-b11.7.

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AbstractAl/PS junctions are non-rectifying and quasi-linear whereas Al/PS/c-Si junctions are weakly rectifying. The rectifying behavior is due to PS/c-Si heterojunction. The diode ideality factor (n) is about 8 for bias ≤0.5 V (about 50 for bias ≤5 V) at forward bias and nearly 1 for ≤0.5 V at reverse bias. As the temperature decreases, n at both forward and reverse biases increases. Different current transport mechanisms are found to be operating across the PS/c-Si junctions under forward and reverse biases. The barrier height measured from I-V data for ≤0.5 V is higher for forward bias than that for reverse bias. For high reverse biases (>5 V), the reverse current increases slowly following In(I)∝ V1/2 law. I-V results on PS/c-Si junctions are explained by a multi tunneling-recombination model for forward bias while carrier generation-recombination and barrier lowering effects for reverse bias.

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49

Zhu, X. F., J. S. Williams, D. J. Llewellyn, and J. C. McCallum. "Microstructure of Ultra High Dose Self Implanted Silicon." MRS Proceedings 504 (1997). http://dx.doi.org/10.1557/proc-504-27.

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ABSTRACTThis study has investigated the microstructure of ultra high dose (∼ 1018 cm−2) self implantation into Si. Implants have been carried out into both (100) Si and pre-amorphised Si as a function of implant temperature between liquid nitrogen temperature and 350°C. Results show that high dose implantation into completely amorphous Si (a-Si) produces layers which regrow quite well during subsequent solid phase epitaxy. In contrast, implantation into crystalline Si (c-Si) or part amorphous/part crystalline Si can lead to rich and varied microstructures at elevated temperatures, even extending to porous-like structures in some cases. Strong dynamic annealing and agglomeration of points defects in c-Si is thought to be responsible for such behaviour.

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50

Nogales, E., B. Méndez, J. Piqueras, and R. Plugaru. "STM-REBIC study of nanocrystalline and crystalline silicon." MRS Proceedings 738 (2002). http://dx.doi.org/10.1557/proc-738-g7.6.

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ABSTRACTElectrically active regions of nanocrystalline silicon (nc-Si) films as well as of a p-type crystalline silicon (c-Si) wafer have been investigated by using a scanning electron microscope/scanning tunneling microscope (SEM/STM) combined instrument. The nc-Si films were obtained by boron implantation of amorphous silicon layers with an average nanocrystal size of about 10 nm. STM current constant images reveal a cell structure in the nc-Si films which was also revealed in the STM remote electron beam induced current (REBIC) images with a resolution of up to 20 nm. The contrast in the STM-REBIC images indicate the existence of space charge regions at the boundaries. The influence of the thermal treatment on the cell structure was studied. For comparison, SEM-REBIC and STM-REBIC images from c-Si wafer were obtained.

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