Добірка наукової літератури з теми "Cu2SnS3 Thin Films"

In this study report the structural and optical properties of Copper Tin Sulfide (Cu2SnS3) thin films on indium tin oxide (ITO) substrate using co-evaporation technique. High purity of copper, tin and sulfur were taken as source materials to deposit Cu2SnS3 (CTS) thin films at different substrate temperatures (200-350 °C). Further, the effect of different substrate temperature on the crystallographic, morphological and optical properties of CTS thin films was investigated. The deposited CTS thin films shows tetragonal phase with preferential orientation along (112) plane confirmed by X-ray diffraction. Micro-Raman studies reveled the formation of CTS thin films. The surface morphology, average grain size and rms values of the deposited films are examined by Scanning electron spectroscopy (SEM) and Atomic Force Microscopy (AFM). The Energy dispersive spectroscopy (EDS) shows the presence of copper, tin and sulfur with a nearly stoichiometric ratio. The optical band gap (1.76-1.63 eV) and absorption coefficient (~105 cm-1) of the films was calculated by using UV-Vis-NIR spectroscopy. The values of refractive index, extinction coefficient and permittivity of the deposited films were calculated from the optical transmittance data.

Copper tin sulfide (Cu2SnS3) thin films have been grown on glasssubstrate with different thicknesses (500, 750 and 1000) nm by flashthermal evaporation method after prepare its alloy from theirelements with high purity. The as-deposited films were annealed at473 K for 1h. Compositional analysis was done using Energydispersive spectroscopy (EDS). The microstructure of CTS powderexamined by SEM and found that the large crystal grains are shownclearly in images. XRD investigation revealed that the alloy waspolycrystalline nature and has cubic structure with preferredorientation along (111) plane, while as deposited films of differentthickness have amorphous structure and converted to polycrystallinewith annealing temperature for high thickness. AFM measurementsshowed that the grain size of the films was increasing by annealing.The ultraviolet- visible absorption spectrum measurement indicatedthat the films have a direct energy band gap. Eg decrease withthickness and increase with annealing.

Le materiau Cu2SnS3 (CTS) est un semi-conducteur caracterisé par une bande interdite direct et un fort coefficient d'absorption optique dans le domaine du visible. Ces propriétés font de lui un des composes les plus attractifs pour une application photovoltaïque en couches minces. Compare aux technologies concurrentes, le CTS tire ces principaux avantages du nombre et de la nature de ses éléments. Ils sont abondants et non toxiques, une tendance encourageante qui promet de développer une future technologie de photopiles a faible cout et respectueuse de l’environnement. L’objectif de ce travail est de réaliser des dépôts de films minces microstructures de CTS a partir de nanoparticules du même matériau. Pour se faire, un protocole expérimental original a été adopte en associant deux procédés d’élaboration simple : hydrothermal et CVD a courte distance. Cette approche a permis de s’affranchir des procédés conventionnels couteux actuellement employés
The Cu2SnS3 compound (CTS) is a semiconductor characterized by a direct band gap and a high optical absorption coefficient in the visible range. These properties make it one of the most attractive materials for thin-film photovoltaic (PV) applications. Compared to competing technologies, CTS derives its main benefits from the number and nature of its constituent elements. They are abundant and non-toxic. This encouraging trend is propitious for the development of future low cost and environmentally friendly solar cell technology. The aim of our study is to develop CTS thin films from the same nanostructured source material. To this end, we have have developed an original experimental procedure, by combining two simple, low-cost and environmentally friendly processes: Hydrothermal and Short-Range CVD. This approach has made it unnecessary to use the conventional costly processes presently employed

Photodetectors are widely used as image sensors, in optical communication, remote sensing etc. IR detectors find widespread applications in night vision cameras and medical diagnostics. In this thesis a new chalcopyrite material Cu2SnS3 has been studied for photodetector applications. Cu2SnS3 has a near IR band gap in the range of 0.93 to 1.5 eV which is optimum for solar light absorption and IR applications. It has a high absorption coefficient of 104 to 105 cm-1 thus suitable for harnessing the solar photons. Thus, Cu2SnS3 can be envisaged as a potential candidate for optical applications such as photodetectors, photovoltaics, light emitting diodes, photocatalysis and nonlinear optics. The thesis deals with the preparation of Cu2SnS3 thin films and nanostructures by solution processable techniques. The electrical transport mechanism in Cu2SnS3 and Cu2SnS3/Al:ZnO heterojunction is studied. The band offsets at the Cu2SnS3/Al:ZnO and Cu2SnS3/ITO heterojunctions are determined using XPS. Finally, the visible and infrared photo response of the Cu2SnS3 thin films, nanostructures and inorganic organic hybrid systems have been investigated. Chapter-1 gives the introduction to the topic of photodetection, the motivation behind the present work and about the material Cu2SnS3. Chapter-2 describes the various synthesis techniques for making Cu2SnS3 films and nanostructures. Also, the characterization techniques for analyzing the Cu2SnS3 material and device fabrication for various optoelectronic applications have been presented. Chapter-3 deals with the preparation of Cu2SnS3 films using a solution processible spin coating method and its characterization using several techniques. The various phase transformations and deposition temperature of the precursor solution was determined using TGA and DSC. The Cu-Sn-thiourea complex precursor was analysed using Fourier Transform Infrared Spectroscopy. The phase formation of the films was determined using X-ray diffraction. The vibrational modes of Cu2SnS3 were deduced using Raman spectroscopy. The structure and morphology of the films as well as the composition were determined from Scanning electron microscopy and Energy dispersive spectroscopy, respectively. The surface morphology of the films and roughness was determined using noncontact mode Atomic force microscopy. The thickness of the deposited films was measured using stylus profilometry. The absorption spectra of the films were obtained using UV-VIS-NIR spectrophotometer. The refractive index, extinction coefficient and relative permittivity were determined using spectroscopic ellipsometry. Electrical properties were measured using Hall effect studies. Chapter-4 discusses the temperature dependent current voltage characteristics of the Cu2SnS3 films. The temperature dependent electrical properties of the drop casted Cu2SnS3 films were measured in the temperature range 140 K to 317 K. The log I versus √V plot showed two regions wherein the region at lower bias was due to electrode limited Schottky emission and the higher bias region was due to bulk limited Poole Frenkel emission. The ideality factor was calculated from the ln I versus V plot for different temperatures fitted with the thermionic emission model and was found to vary from 5.6 to 8.13. This large value was attributed to the presence of defects or amorphous layer at the Ag / Cu2SnS3 interface. From the Richardson’s plot the Richardson’s constant and the barrier height were calculated. Owing to the inhomogeneity in the barrier heights, the Richardson’s constant and the barrier height were also calculated from the modified Richardson’s plot. The temperature dependent current graphs showed two regions of different mechanisms. The log I versus 1000/T plot gave activation energies Ea1 = 367.1 – 257.68 meV and Ea2 = 38.42 - 42.45 meV. The log (I/T2) versus 1000/T graph gave trap depths Φo1 = 314.16 - 204.75 meV and Φo2 = 7.43 - 11.16 meV. With increasing voltage, the activation energy Ea1 and the trap depth Φo1 decreased. From the ln (IT1/2) versus 1/T1/4 graph, the low temperature region was attributed to variable range hopping mechanism and the high temperature region was attributed to thermionic emission. Chapter-5 deals with the study of the band offsets at the Al:ZnO/Cu2SnS3 heterojunction interface using X-ray photoelectron spectroscopy. Al: ZnO/Cu2SnS3 semiconductor heterojunction was fabricated. The structural and optical properties of the semiconductor materials were studied. From the measurement of the core level energies and valence band maximum of the constituent elements, the valence band offset was calculated to be -1.1 0.24 eV and the conduction band offset was 0.9 0.34 eV. The band alignment at the heterojunction was found to be of type-I. The variation of the current transport behavior as a function of temperature was studied for the heterojunction. The log I - log V plot exhibited three regions of different slopes showing linear ohmic behaviour and non-linear behaviour following the power law. There was a variation in the ideality factor and barrier height with temperature. The Richardson constant was calculated and its deviation from the theoretical value revealed the inhomogeneity of the barrier heights. Transport characteristics were modelled using the thermionic emission model. The Gaussian distribution of barrier heights was applied and from the modified Richardson plot the value of the Richardson constant was found to be 47.18 Acm-2K-2. Chapter-6 deals with the study of band offsets at the Cu2SnS3 / In2O3: Sn interface using X-ray photoelectron spectroscopy. Cu2SnS3 thins films were ddeposited onto In2O3: Sn coated soda lime glass substrates by spin coating technique. The films were structurally characterized using X-Ray Diffraction and Atomic Force Microscopy. The morphology of the films was studied using Field Emission Scanning Electron Microscopy. The optical properties of the films were determined using UV-Vis-NIR spectrophotometer. The electrical properties were measured using Hall effect measurements. The energy band offsets at the Cu2SnS3/In2O3: Sn interface were calculated using X-ray photoelectron spectroscopy. The valence band offset was found to be -3.40.24 eV. From the valence band offset value, the conduction band offset was calculated to be -1.950.34 eV. The energy band alignment indicates a type-III heterostructure formation. Chapter-7 deals with the study of the visible and infrared photo response of Cu2SnS3 thin films. The Cu2SnS3 thin films were deposited using an economic, solution processible, spin coating technique. The films were found to possess a tetragonal crystal structure using X-ray diffraction. The film morphology and the particle size were determined using scanning electron microscopy. The various planes in the crystal were observed using transmission electron microscopy. The optimum band gap of 1.4 eV and a high absorption coefficient of 104 cm-1 corroborate its application as a photoactive material. The visible and infrared (IR) photo response was studied for various illumination intensities. The current increased by one order from a dark current of 0.31 A to a current of 1.78 A at 1.05 suns and 8.7 μA under 477.7 mW/cm2 IR illumination intensity, at 3 V applied bias. The responsivity, sensitivity, external quantum efficiency and specific detectivity were found to be 10.93 mA/W, 5.74, 2.47% and 3.47 × 1010 Jones respectively at 1.05 suns and 16.32 mA/W, 27.16, 2.53% and 5.10 × 1010 Jones respectively at 477.7 mW/cm2 IR illumination. The transient photo response was measured both for solar and IR illuminations. Chapter-8 deals with the incorporation of Cu2SnS3 in visible and infrared photodetector applications. Various device structures such as Cu2SnS3 nanostructures and Cu2SnS3 nanostructures-P3HT-PCBM inorganic-organic hybrids were used. The visible and infrared photo response as well as the time dependent photo response was studied. The sensitivity, responsivity, external quantum efficiency and specific detectivity were measured. Chapter- 9 presents the summary and the future work

碩士
國立臺南大學
電機工程學系碩博士班
103
In this study, we investigated the ternary I–IV–VI compounds semiconductor layer synthesized by a simple and low-cost solvent-thermal refluxing method follow annealing. The thin films are suitable to be absorber layer of solar cells. At first, we fabricated the varied concentration of Cu-Sn-S precursor ink. After sulfurization, we obtained pure phase of CTS by sulfurizing the Cu-Sn-S precursor of the lower concentration. The CTS thin film is p-type with a carrier concentration of ∼5.23×1017 cm-3, and hole mobility of 14.2 cm2 V−1 s−1, which is suitable to be absorber layer of solar cells. We fabricated the Cu-Sn-Se precursor ink by different reaction time. At the longer reaction time, we obtained pure phase of CTSe. At the shorter reaction time, we obtained Cu2-xSe crystals and unformed Cu-Sn-Se groups. After selenization, the structures of Cu2SnSe3 were destructured and binary CuSe appeared. In contrast, after selenization, the precursors of short reaction time transform into pure Cu2SnSe3. The CTSe thin film is p-type with a carrier concentration of ∼1.9×1017 cm−3, and higher hole mobility of 13.66 cm2 V−1 s−1, which is suitable to be absorber layer of solar cells. In this study, we fabricated the ternary I–IV–VI compounds thin films by a simple and low-cost solvent-thermal refluxing method and and annealing.

碩士
國立臺灣科技大學
材料科學與工程系
103
Due to the energy crisis, we rush into the solar cell research and development. Fulfillment of energy is an issue that is always covered by each of the countries, coupled with the increasing rate of world population growth the energy consumption will continue to increase. Solar cell is one of the best choices, solar cells has been studied for more than fifty years but the last decade has seen the drastic growth in the research and development in the sector and because of that, now we have so many different types of solar cells design with megawatt production capabilities. Modern solar cells design can be fabricated using different materials and can have different structure. Cu2SnSe3 (CTSe) is a potential candidate for absorber materials of solar cells. In this study, we report the effects of doping Mg on the structural, electrical, and optical properties of these CTSe thin films for devolepment of highly efficient solar cells for long term energy production. Thin films of the CTSe and Mg-doped CTSe were sputtered with two different targets of Cu and Sn or Cu-Mg and Sn, respectively , followed by the selenization at 500-600 oC under the Se vapor. The films were characterized by FE-SEM, EDS, XRD, and Hall measurement and other analyses to explore the effects of Mg-doping with different ratios on CTSe thin film. All the thin films CTSe and Mg-doped CTSe were deposited by DC magnetron co-sputtering at room temperature with the powers of 26 W for Cu target and 16 W for Sn target for CTSe thin films and 26 W for Cu-Mg target and 16 W for Sn target for Mg-CTSe for 1hour. A two-step selenization process was executed at 300 oC and holding period of 30 min before reaching to three different selenization temeperatures of 500 oC, 550 oC, and 600 oC. The selenization procedure had been done in Se ambient arisen from SnSe2 pellet. Almost all thin films selenized at 550 oC-selenized films had the composition closed to expected stoichiometry of Cu2SnSe3. The major XRD diffraction peaks appeared at 2θ of 26.8°, 44.8°, 53.2°, 65.5°, and 72.3° which could be attributed to (111), (220), (311), (400), and (331) planes, respectively. All the diffraction peaks of CTSe could be assigned to the crystal planes from standard structure of Cu2SnSe3 (JCPDS No.89-2879). The optical band gaps obtained by extrapolating the linear region of the absorption spectra did not significantly change. The optical absorption studies indicated a direct band gap of 1.18 ~ 1.20 eV. Undoped CTSe and Mg-0.1-CTSe films selenized at 550 oC exhibited p-type conductivity and they were n-type for Mg-0.2-CTSe and Mg-0.3-CTSe. The Hall measurements for carrier concentration and Hall mobility were 2.54×1019 cm−3 and 681 cm2V−1s−1, respectively, for undoped CTSe film, 9.08 ’ 1018 cm-3 and 71 cm2V-1s-1 for Mg-0.1-CTSe, 1.18 ’ 1019cm−3 and 11 cm2V−1s−1 for Mg-0.2-CTSe, and 1.06 ’ 1019cm−3 and 43 cm2V−1s−1 for Mg-0.3-CTSe, after selenization at 550 oC.

碩士
國立臺灣科技大學
材料科技研究所
97
Recently, the research of solar cells is much more attractive and its technological progress is very fast. Although solar cells have reached a good conversion efficiency, high cost has limited their further applications. Lowering the cost with the finding of new materials is necessary. Although there are many CuInSe2 replacements, low-cost Cu2SnSe3 thin films with an energy band gap of 0.7-0.9 eV have not been seriously investigated for the absorption layer of the solar cells. In this study, the effects of the target composition, substrate temperature, annealing temperature, and the Se compensating discs on the sputtered Cu2SnSe3 thin films are discussed. The physical characteristics of the Cu2SnSe3 thin films were invstigated by XRD, FE-SEM, and EDS XRD. Hall measurement and Absorption spectroscopy were used for the electrical and optical properties, respectively. The experimental results shows that the sputtered Cu2SnSe3 thin films deposited at 400oC followed by annealing at 500oC have a better performance. At this condition, the films are p-type and have well crystallized with a large grain size of 1-3 �慆, a direct energy gap of 0.7-0.8 eV, an absorption coefficient of 104 cm-1 before and after annealing, a carrier concentration of 5×1019 cm-3, and the highest carrier mobility of 8~10 cm2V-1s-1.

碩士
國立虎尾科技大學
材料科學與綠色能源工程研究所
102
In this study, ternary Cu2SnSe3 thin films were synthesized by non-vacuum processes. First of all, Cu, Sn and Se elements with different ratio, were melted in quartz tubes at 1050 oC to form ingots from Cu-poor, stoichiometric to Cu-rich mixtures (Cu/Sn atomic ratio = 1.5, 2.0 and 2.5, respectively). Inks of the mixtures were made using wet-type ball milling, and printed onto a glass substrate to form a precursor film by spin coating. Then, the samples were heated with rapid thermal annealing(RTA) in a furnace at 300 to 550 oC, respectively, for 10 minutes. The compositions of the films were determined by inductively coupled plasma-mass spectrometer (ICP) and energy dispersive spectroscopy (EDS) measurements. Surface and cross-section morphologies were observed by scanning electron microscopy (SEM). The crystal structure of the films was analyzed by X-ray diffraction (XRD) and the band gaps were obtained by Photoluminescence (PLE) measurement. Optical properties were recorded by UV-Vis-NIR spectrometer. Based on the results of the experiments, the thin films (Cu/Sn atomic ratio = 1.5) with sphalerite structure were obtained by RTA 450 oC , 10 minutes. It also showed higher crystallinity with larger grain size, and the band gap was 1.00eV.

碩士
國立成功大學
微電子工程研究所碩博士班
97
This thesis investigated the possible reaction route of quaternary semiconductor Cu2ZnSnSe4 (CZTSe) absorber synthesized by surface Zn diffusion to underneath Copper-Tin-Selenide ternary layer at 500oC. The electrical property of CZTSe was also investigated for the first time. In this thesis, Zn thickness and duration of annealing were optimized to fabricate near stoichiometric CZTSe film. Single phase CZTSe was produced by annealing 300 nm Zn/2.65 um Cu2SnSe3 at 500oC for 1.5 hours. Raman scattering analysis was used to identified the phase transformation from Cu2SnSe3 to CZTSe. It also showed that the synthesized film was single phase CZTSe without ZnSe binary compound. Hall measurement results showed that these films are p-type with low resistivity and high carrier concentration of 1021cm-3. Finally, the insufficient Se ratio problem was resolved by replacing the of Cu-Sn selenization temperature from 450oC to 250oC so as to increase the incorpoaration of Se with Cu and Sn to form CuSe2 and SnSe instead of ternary. CZTSe film with grain size up to 1.5 um and nearly stichiometric ratio was obtained.

碩士
國立虎尾科技大學
材料科學與綠色能源工程研究所
103
The experiment is investigate on the application of Cu2ZnSn(SSe)4 for solar cell absorber layer materials. First of all, copper, tin, selenium the three elements, prepared by melting into the ternary mixture, and adding a binary synthesis (ZnS)compound to mix, the ink is prepared using wet-ball milling , Cu/Zn+Sn atomic ratio were 0.6、0.8、1、1.5，by spin coating. The precursor layer is placed in RTP furnace, and then heated at the temperature between 300 oC to 500oC,respectively, for 10minutes，prepared Cu2ZnSn(SSe)4 2-3μm thick film.In passing a high purity nitrogen gas under high temperature by diffusion。 The compositions of the films were determined by inductively coupled plasma-mass spectrometer(ICP)measurements，Surface and cross-section morphologies were observed by scanning electron microscopy.The crystal structure of the films was analyzed by X-ray diffraction .Optical properties were recorded by UV-Vis-NIR spectrometer. Based on the results of the experiments, the thin films (Cu/Zn+Sn atomic ratio = 0.8) with Better crystalline were obtained by RTA 500 oC , 10 minutes. It also showed higher crystallinity with larger grain size, and the band gap was 1.44eV.

碩士
國立臺南大學
電機工程學系碩博士班
106
Abstract In this paper, a simple, low-cost non-vacuum solvothermal refluxing method is used to obtain a I-IV-VI ternary compound Cu2SnSe3(CTSe) film after selenization heat treatment. The CTSe film is suitable as an absorber layer for light sensors and thin film solar cells. First, we successfully synthesized a mixed nano ink of Cu2Se and SnSe2 and CuSe and SnSe2 by adding a new organic solvent Polyetheramine(D400) by non-vacuum solvothermal reflux method, and both used a stoichiometric ratio of 2:1:3. The ratio of copper, tin and selenium was obtained by heat treatment by selenization to obtain a ternary single phase Cu2SnSe3(CTSe) film. The former has a selenization temperature of 550°C and the heating time is 5 minutes, while the latter has a selenization temperature of 550°C and a heating time of 15 minutes. Finally, because the quality of the film is not enough for us to make further applications, so we will try to look at the new preparation method to improve the crystallization and compactness of the film in the next chapter. Next, in order to improve the quality of the film, Cu2SnSe3(CTSe) single phase and CuSe and SnSe2 hybrid phase precursor film were successfully prepared by non-vacuum solvothermal refluxing method and centrifugal powders and blade coating. CTSe ternary single phase was obtained by rapid selenization heat treatment under pressure. The best conditions for the two groups are a selenization temperature of 500°C and a heating time of 60 minutes. Finally, compared to the experimental method in the previous chapter, we think this is a way to find an improvement. Although the crystallinity and compactness have a certain degree of improvement in quality, but the quality of the film after selenization may not be very stable, so we can still carry out more tests and compare the operation methods of the blade coating, to continue to do related applications.

碩士
國立臺南大學
電機工程學系碩博士班
105
In this education, we examined the ternary I–IV–VI mixes semiconductor layer synthesized by a humble and low-cost solvent-thermal refluxing method follow annealing. The thin films are appropriate to be absorber layer of solar cells. Cu-containing ternary chalcogenides (Cu2SnSe3) were positively synthesized by stoichiometric amount of the preliminary resources via a simple and suitable solvent-thermal-reflux reaction of copper powder, tin powder with selenium powder in the time variety of 30min-12hr for 150℃、190℃、230℃. In this study, we firstly examine nonvacuum process polyetheramine synthesized Cu2SnSe3 (CTSe) nanoink creation device based on time reliant on phase development and particle nucleation and development. We fabricated the Cu-Sn-Se precursor hybrid nanoink by different reaction time. After selenization, the structures of Cu2SnSe3 were destructured and binary CuSe seemed. In contrast, after selenization, the precursors of short reaction time alter into pure Cu2SnSe3. The CTSe thin film is p-type with a carrier concentration of ∼1.9×1019 cm−3, and higher hole mobility of 13.66 cm2 V−1 s−1, which is suitable to be absorber layer of solar cells. In this study, we fabricated the ternary I–IV–VI compounds thin films by a simple and low-cost solvent-thermal refluxing method and and annealing.