Dissertations / Theses on the topic 'Metal chalcogenide films'
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Pearce, Amber Marie. "Synthesis and characterisation of metal chalcogenide thin films." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/synthesis-and-characterisation-of-metal-chalcogenide-thin-films(7a22c662-639c-4aaf-a4cc-f2ae655115c0).html.
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There is much interest in the electronic potential of ‘nano’-semiconductors. The avenue of research pursued in this project was in inorganic analogues of graphene, namely metal chalcogenides MxEy (M = metal, E = S, Se, Te, x ≠ y = integer value). Thin films of these materials have been used in solar cells, ambient thermoelectric generators and IR detectors, due to their interesting properties, such as: optoelectronics, magnetooptic, piezoelectric, thermoelectric and photovoltaic, as well as electrical conductivity. The key issues with the use of these materials are the formation of controlled films, especially in terms of stoichiometry, crystallinity and uniformity, and also the precursor system used. The aim of this research was to synthesise and isolate novel precursor compounds for use in the deposition of metal sulfide thin films (for use with molybdenum and tungsten). The potential viability of the compounds as single source precursors (ssp) was judged following ThermoGravimetric Analysis (TGA). The compounds were also subjected to analysis using NMR (1H, 13C and 31P where applicable), infrared and UV-Vis spectroscopy, as well as elemental analysis. Cadmium sulfide (CdS) is one of the key direct band gap II-VI semiconductors, having vital optoelectronic applications for laser light-emitting diodes, and optical devices based on non-linear properties. The ratio of these films should ideally be 1:1, however, during the formation of cadmium sulfide films, particularly at elevated temperatures, a common problem encountered is the production of sulfur deficient films. These films have a formula consistent with 〖Cd〗_x S_y, where x is an integer value greater than y, but the sulfur deficiency is generally no greater than 10 %. In order to correct this sulfur deficiency, it was decided to investigate deposition making use of both a ssp and an additional sulfur source, with the aim of producing uniform films with 1:1 Cd:S.Molybdenum disulfide films have been deposited previously from multi source precursors and more recently using ssp. In this project MoS2 was deposited using novel ssps in both LP and AACVD on a variety of substrates with the aim of producing uniform thin films and assessing any differences in the morphology of the deposition. This work was continued with the deposition of WS2 and MoxW1-xS2 from ssps which had not been reported previously. The films deposited were analysed using XRD, SEM, EDX (when available) and Raman spectroscopy.
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Volkmann, Christian. "Atomic layer deposition of metal and metal chalcogenide thin films and nanolaminate composites." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2017. http://hdl.handle.net/11858/00-1735-0000-002E-E3AE-5.
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Redman, Helen. "The growth of transition metal chalcogenide thin films using chemical vapour deposition." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312584.
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Ezenwa, Emmanuel. "N,N-diethyl-N'-naphthoylacylchalcogourea to metal (II)complexes as precursors for ternary metal chalcogenide thin films via AACVD." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/nndiethylnnaphthoylacylchalcogoureatometal-iicomplexes-as-precursors-for-ternary-metal-chalcogenide-thin-films-via-aacvd(85420a4c-89d4-4465-9734-ca40a75ba924).html.
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In this thesis complexes of acylchalcogoureas with cadmium (II), lead (II) and nickel (II) have been synthesised and investigated as single source precursors for the formation of metal chalcogenide thin films viaaerosol assisted chemical vapour deposition (AACVD). Routes to binary thin films have been explored using homoleptic complexes of the general structure bis(N,N-diethyl-N'-naphthoylchalcogoureato)metal(II). Analysis of the thin films produced showed the successful deposition of the binary materials from the synthesised complexes when characterised by powder XRD, ICP-OES, SEM and EDX. Routes to ternary thin films with the general structure MExE'1-x, where M represents a metal (Cd, Ni and Pb); and E chalcogen (S or Se) have been investigated using heteroleptic metal complexes of cadmium, nickel or lead including different chalcogen containing N,N-diethyl-N'-naphthoylchalcogoureato ligands and diethyldithiocarbamate. The precursors were fully characterised and novel compounds had their crystal structures determined. The heteroleptic complexes were thermolysed by AACVD forming the MExE'1-x thin films. In the cases of lead, nickel and cadmium the thin films produced showed that the composition of the film tended heavily towards the metal selenide. Ternary films of type MS1-xSex was prepared by mixing their binary precursors of type bis(N,N-diethyl-N'-naphthoylselenoureato)metal(II) and bis(N,N-diethyl-N'-naphthoylthioureato)metal(II) [metal = Cd, Ni and Pb]. In the case of lead and cadmium chalcogenide films variation of the ratio of sulphur and selenium containing precursors allowed for the full transition in composition between metal sulphide and metal selenide. In the case of CdS1-xSexthe band gap of the films was determined from UV-visible spectroscopy to vary from 2.4 eV (CdS) to 1.7 eV(CdSe). In the case of NiS1-xSex the movement from sulphide to selenide was less simple with multiple phases of nickel chalcogenides produced.
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Chang, Yao-Pang. "Complexes of Group V and VI metals with soft donor ligands : towards reagents for early metal chalcogenide thin films." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/417996/.
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Preparations of NbX4 (X = Cl, Br) have been developed in good yield, leading to the formation of a series of 2:1 and 1:1 adducts upon reaction with neutral diphosphine ligands. The 2:1 ligand:metal complexes [NbX4(P–P)2] (X = Cl, Br; P–P = Me2P(CH2)2PMe2, Et2(CH2)2PEt2, o-C6H4(PMe2)2) were characterised by IR and UV-visible spectroscopies, their purities determined by microanalysis and the solid-state structures confirmed by X-ray crystallography to be that of eight coordinate dodecahedra or square antiprisms. The dimeric 1:1 complexes [Nb2X4(P–P)2(μ-X)4] (P–P = Me2P(CH2)2PMe2, Et2P(CH2)2PEt2, Ph2P(CH2)3PPh2, Cy2P(CH2)2PCy2, o-C6H4(PPh2)2) were also characterised by 1H and 31P{1H} NMR spectroscopy. A series of six-coordinate monomeric complexes, [NbCl4(L–L)] (L–L = MeS(CH2)2SMe, iPrS(CH2)2SiPr, MeS(CH2)3SMe, o-C6H4(CH2SEt)2, MeSe(CH2)2SeMe, MeSe(CH2)3SeMe and nBuSe(CH2)3SenBu) and [NbCl4(ER2)2] (ER2 = SMe2, SeMe2, SenBu2 and TeMe2) were prepared from NbCl4 and the ligand in CH2Cl2 solution. X-ray structures show that most of them form six-coordinate octahedral complexes, whereas [NbCl4(SeMe2)2] and [NbCl4(TeMe2)2] are thought to be dimeric from X-ray crystallography of the latter. The Nb(IV) complexes were unsuitable as CVD precursors. Monomeric [NbSCl3(L–L)] (L–L = MeS(CH2)2SMe, iPrS(CH2)2SiPr, MeS(CH2)3SMe, nBuS(CH2)3SnBu and MeSe(CH2)3SeMe) and dimeric [NbSCl3(SR2)] (R = Me and nBu) were prepared from reaction of [NbSCl3(NCCH3)2] with the ligand in CH2Cl2 solution or reaction of [NbCl5(SR2)] with S(SiMe3)2 in CH2Cl2 solution and characterised by IR, 1H NMR and 93Nb NMR spectroscopies, X-ray crystallography and microanalysis. Isolated complexes [NbSenCl3(L)] (n = 1, L = CH3CN; n = 2, L = nBu2Se) were identified by IR spectroscopy and microanalysis. [NbSCl3(SnBu2)], [NbSCl3(nBuS(CH2)3SnBu)] and [NbSe2Cl3(SenBu2)] were used as single source precursors in LPCVD. The resulting NbS2 and NbSe2 thin films were characterised via X-ray diffraction, SEM and EDX spectroscopy. Isolated complexes of the form, [MBr5(EnBu2)] (M = Nb, Ta; E = S, Se), were identified via IR and multinuclear NMR spectroscopies and the Nb complexes were used as single source precursors in LPCVD to deposit NbS2 and NbSe2 thin films. The growth of 2H-/3R-NbSe2 thin films was controlled by varying the temperature used in LPCVD. All NbS2 and 2H-/3R-NbSe2 thin films were characterised using X-ray diffraction, SEM and EDX spectroscopies. A series of new MoCl4 complexes, [MoCl4(ER2)2] (ER2 = Me2S, Me2Se, nBu2S, nBu2Se) and [MoCl4(L–L)] (L–L = MeS(CH2)2SMe, iPrS(CH2)2SiPr, MeS(CH2)3SMe, and MeSe(CH2)3SeMe), were made using MoCl5 or [MoCl4(NCCH3)2] as the Mo source and characterised using IR and UV-visible spectroscopies, X-ray crystallography and microanalysis. Single source LPCVD precursors, [MoCl4(SnBu2)2] and [MoCl4(SenBu2)2], deposited MoS2 or MoSe2 thin films which were characterised via X-ray diffraction, SEM and EDX spectroscopy.
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Junaghadwala, Sakina Mohsin. "Metal Modified Ge-Se Glass Films and Their Potential for Nanodipole Junctionless Photovoltaics." University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1320061322.
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Volkmann, Christian [Verfasser], Sven [Akademischer Betreuer] Schneider, Dietmar [Gutachter] Stalke, Inke [Gutachter] Siewert, Selvan [Gutachter] Demir, Guido [Gutachter] Clever, and Thomas [Gutachter] Waitz. "Atomic layer deposition of metal and metal chalcogenide thin films and nanolaminate composites. / Christian Volkmann ; Gutachter: Dietmar Stalke, Inke Siewert, Selvan Demir, Guido Clever, Thomas Waitz ; Betreuer: Sven Schneider." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2018. http://d-nb.info/1172500754/34.
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Cuthbert, Edwin. "The synthesis of metal chalcogenide volatile precursors in the formation of antimony and bismuth sulphide thin films and the synthesis of amine adducts for the formation of gallium nitride by MOCVD." Thesis, University of Reading, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250737.
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Zella, Leo W. "Metal Ion Diusion in Thin Film Chalcogenides." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1467075804.
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Jürgensen, Lasse [Verfasser]. "Thin Films of Transition Metal Chalcogenides: Novel Molecular Pathways and Catalytic Applications / Lasse Jürgensen." München : Verlag Dr. Hut, 2021. http://d-nb.info/1232846740/34.
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Belke, Christopher [Verfasser]. "Untersuchung von Dünnschicht-Übergangsmetall-Chalkogeniden hinsichtlich ihrer elektrischen Eigenschaften : Investigation of thin film transition metal chalcogenides regarding their electrical properties / Christopher Belke." Hannover : Gottfried Wilhelm Leibniz Universität, 2021. http://d-nb.info/1230550666/34.
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"Response of Metal Structures on Chalcogenide Thin Films to Thermal, Ultraviolet and Microwave Processing." Master's thesis, 2013. http://hdl.handle.net/2286/R.I.18719.
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abstract: Microwave (MW), thermal, and ultraviolet (UV) annealing were used to explore the response of Ag structures on a Ge-Se chalcogenide glass (ChG) thin film as flexible radiation sensors, and Te-Ti chalcogenide thin films as a material for diffusion barriers in microelectronics devices and processing of metallized Cu. Flexible resistive radiation sensors consisting of Ag electrodes on a Ge20Se80 ChG thin film and polyethylene naphthalate substrate were exposed to UV radiation. The sensors were mounted on PVC tubes of varying radii to induce bending strains and annealed under ambient conditions up to 150 oC. Initial sensor resistance was measured to be ~1012 Ω; after exposure to UV radiation, the resistance was ~104 Ω. Bending strain and low temperature annealing had no significant effect on the resistance of the sensors. Samples of Cu on Te-Ti thin films were annealed in vacuum for up to 30 minutes and were stable up to 500 oC as revealed using Rutherford backscattering spectrometry (RBS) and four-point-probe analysis. X-ray diffractometry (XRD) indicates Cu grain growth up to 500 oC and phase instability of the Te-Ti barrier at 600 oC. MW processing was performed in a 2.45-GHz microwave cavity on Cu/Te-Ti films for up to 30 seconds to induce oxide growth. Using a calibrated pyrometer above the sample, the temperature of the MW process was measured to be below a maximum of 186 oC. Four-point-probe analysis shows an increase in resistance with an increase in MW time. XRD indicates growth of CuO on the sample surface. RBS suggests oxidation throughout the Te-Ti film. Additional samples were exposed to 907 J/cm2 UV radiation in order to ensure other possible electromagnetically induced mechanisms were not active. There were no changes observed using XRD, RBS or four point probing.Dissertation/Thesis
M.S. Materials Science and Engineering 2013
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Altschul, Emmeline Beth. "Transition metal solar absorbers." Thesis, 2012. http://hdl.handle.net/1957/33382.
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A new approach to the discovery of high absorbing semiconductors for solar cells was taken by working under a set of design principles and taking a systemic methodology. Three transition metal chalcogenides at varying states of development were evaluated within this framework. Iron pyrite (FeS���) is well known to demonstrate excellent absorption, but the coexistence with metallic iron sulfides was found to disrupt its semiconducting properties. Manganese diselenide (MnSe���), a material heavily researched for its magnetic properties, is proposed as a high absorbing alternative to iron pyrite that lacks destructive impurity phases. For the first time, a MnSe��� thin film was synthesized and the optical properties were characterized. Finally, CuTaS���, a known but never characterized material, is also proposed as a high absorbing semiconductor based on the design principles and experimental results.Graduation date: 2013
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Biswas, Kanishka. "Synthesis, Characterization, Properties And Growth Of Inorganic Nanomaterials." Thesis, 2008. http://hdl.handle.net/2005/706.
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The thesis consists of eight chapters of which the first chapter presents a brief overview of inorganic nanostructures. Synthesis and magnetic properties of MnO and NiO nanocrystals are described in Chapter 2, with emphasis on the low-temperature ferromagnetic interactions in these antiferromagnetic oxides. Chapter 3 deals with the synthesis and characterizations of nanocrystals of ReO3, RuO2 and IrO2 which are oxides with metallic properties. Pressure-induced phase transitions of ReO3 nanocrystals and the use of the nanocrystals for carrying out surface-enhanced Raman spectroscopy of the molecules form Chapter 4. Use of ionic liquids to synthesize different nanostructures of semiconducting metal sulfides and selenides is described in Chapter 5. Synthesis of Mn-doped GaN nanocrystals and their magnetic properties are described in Chapter 6.
A detailed investigation has been carried out on the growth kinetics of nanostructures of a few inorganic materials by using small-angle X-ray scattering and other techniques (Chapter 7). The study includes the growth kinetics of nanocrystals of Au, CdS and CdSe as well as of nanorods of ZnO. Results of a synchrotron X-ray study of the formation of nanocrystalline gold films at the organic-aqueous interface are also included in this chapter.
Chapter 8 discuses the use of the organic-aqueous interface to generate Janus nanocrystalline films of inorganic materials where one side of the film is hydrophobic and other side is hydrophilic. This chapter also includes the formation of nanostructured peptide fibrils at the organic-aqueous interface and their use as templates to prepare inorganic nanotubes.
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"Characterization of Solution-processed Metal Chalcogenide Precursor, Thin Film, and Nanocomposite for Thermoelectricity." Doctoral diss., 2020. http://hdl.handle.net/2286/R.I.57121.
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abstract: Satisfying the ever-increasing demand for electricity while maintaining sustainability and eco-friendliness has become a key challenge for humanity. Around 70% of energy is rejected as heat from different sectors. Thermoelectric energy harvesting has immense potential to convert this heat into electricity in an environmentally friendly manner. However, low efficiency and high manufacturing costs inhibit the widespread application of thermoelectric devices. In this work, an inexpensive solution processing technique and a nanostructuring approach are utilized to create thermoelectric materials. Specifically, the solution-state and solid-state structure of a lead selenide (PbSe) precursor is characterized by different spectroscopic techniques. This precursor has shown promise for preparing thermoelectric lead selenide telluride (PbSexTe1-x) thin films. The precursor was prepared by reacting lead and diphenyl diselenide in different solvents. The characterization reveals the formation of a solvated lead(II) phenylselenolate complex which deepens the understanding of the formation of these precursors. Further, using slightly different chemistry, a low-temperature tin(II) selenide (SnSe) precursor was synthesized and identified as tin(IV) methylselenolate. The low transformation temperature makes it compatible with colloidal PbSe nanocrystals. The colloidal PbSe nanocrystals were chemically treated with a SnSe precursor and subjected to mild annealing to form conductive nanocomposites. Finally, the room temperature thermoelectric characterization of solution-processed PbSexTe1-x thin films is presented. This is followed by a setup development for temperature-dependent measurements and preliminary temperature-dependent measurements on PbSexTe1-x thin films.Dissertation/Thesis
Doctoral Dissertation Materials Science and Engineering 2020
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(11146737), Swapnil Dattatray Deshmukh. "UNVEILING THE AMINE-THIOL MOLECULAR PRECURSOR CHEMISTRY FOR FABRICATION OF SEMICONDUCTING MATERIALS." Thesis, 2021.
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Inorganic metal chalcogenide materials are of great importance in the semiconducting field for various electronic applications such as photovoltaics, thermoelectrics, sensors, and many others. Compared to traditional vacuum processing routes, solution processing provides an alternate cost-effective route to synthesize these inorganic materials through its ease of synthesis and device fabrication, higher material utilization, mild processing conditions, and opportunity for roll-to-roll manufacturing. One such versatile solution chemistry involving a mixture of amine and thiol species has evolved in the past few years as a common solvent for various precursor dissolutions including metal salts, metal oxides, elemental metals, and chalcogens.
The amine-thiol solvent system has been used by various researchers for the fabrication of inorganic materials, but without the complete understanding of the chemistry involved in this system, utilizing its full potential, and overcoming any inherent limitations will be difficult. So, to identify the organometallic complexes and their reaction pathways, the precursor dissolutions in amine-thiol solutions, specifically for elemental metals like Cu, In and chalcogens like Se, Te were studied using X-ray absorption, nuclear magnetic resonance, infrared, and Raman spectroscopy along with electrospray ionization mass spectrometry techniques. These analyses suggested the formation of metal thiolate complexes in the solution with the release of hydrogen gas in the case of metal dissolutions confirming irreversibility of the dissolution. Insights gained for chalcogen dissolutions confirmed the formation of different species like monoatomic or polyatomic clusters when different amine-thiol pair is used for dissolution. Results from these analyses also identified the role of each component in the dissolution which allowed for tuning of the solutions by isolating the complexes to reduce their reactivity and corrosivity for commercial applications.
After identifying complexes in metal dissolution for Cu and In metals, the decomposition pathway for these complexes was studied using X-ray diffraction and gas chromatography mass spectrometry techniques which confirmed the formation of phase pure metal chalcogenide material with a release of volatile byproducts like hydrogen sulfide and thiirane. This allowed for the fabrication of impurity-free thin-film Cu(In,Ga)S2 material for use in photovoltaic applications. The film fabrication with reduced carbon impurity achieved using this solvent system yielded a preliminary promising efficiency beyond 12% for heavy alkali-free, low bandgap CuInSe2 material. Along with promising devices, by utilizing the understanding of the chalcogen complexation, a new method for CuInSe2 film fabrication was developed with the addition of selenide precursors and elemental selenium which enabled first-ever fabrication of a solution-processed CuInSe2 thin film with thickness above 2 μm and absence of any secondary fine-grain layer.
Along with thin-film fabrication, a room temperature synthesis route for lead chalcogenide materials (PbS, PbSe, PbTe) with controlled size, shape, crystallinity, and composition of nanoparticle self-assemblies was demonstrated. Micro-assemblies formed via this route, especially the ones with hollow-core morphology were subjected to a solution-based anion and cation exchange to introduced desired foreign elements suitable for improving the thermoelectric properties of the material. Adopting from traditional hot injection and heat up synthesis routes, a versatile synthesis procedure for various binary, ternary, and quaternary metal chalcogenide (sulfide and sulfoselenide) nanoparticles from elemental metals like Cu, Zn, Sn, In, Ga, and Se was developed. This new synthesis avoids the incorporation of impurities like O, Cl, I, Br arising from a traditional metal oxide, halide, acetate, or other similar metal salt precursors giving an opportunity for truly impurity-free colloidal metal chalcogenide nanoparticle synthesis.