MOCVD of group III chalcogenides (original) (raw)
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Liquid Film Deposition of Chalcogenide Thin Films
Journal of Sol-gel Science and Technology - J SOL-GEL SCI TECHNOL, 2003
Thin films of MoSx were prepared by liquid film deposition of MoS42- solutions in 1,2-diaminoethane (en) and 1,2-diaminopropane (pn) and subsequent thermolysis at temperatures up to 800°C under N2. As the coatings show a high carbon content of up to 30 at.% that influences the morphology and the physical properties, the precursor thermolysis and the solution properties were analysed in detail and correlated to the coating properties. A reduction of the intermediately formed MoS3 by organic residues at approx. 300°C was made out as the main cause of the carbon contamination during the thermolysis of the precursor salts (enH2)MoS4 and (pnH2)MoS4, leading to an immobilisation of the organic carbon. In the corresponding solutions cations of the form [RNH2...H...NH2R]+ could be detected, that result in an incorporation of additional diamine with 3–4 molecules per MoS42- ion in the wet films. This cross-linked structure on the one hand reduces the tendency of the precursor salts to crysta...
Chemical deposition method for metal chalcogenide thin films
Materials Chemistry and Physics, 2000
... are described. Theoretical background necessary for the chemical deposition of thin films is also discussed. Author Keywords: Metal chalcognide thin films; Thin solid films; Chemical bath deposition. Corresponding Author Contact Information Corresponding author. ...
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This commmunication presents a study of atomic layer deposition of Al 2 O 3 on transition metal dichalcogenide (TMD) two-dimensional films which is crucial for use of these promising materials for electronic applications. Deposition of Al 2 O 3 on pristine chemical vapour deposited MoS 2 and WS 2 crystals is demonstrated. This deposition is dependent on the number of TMD layers as there is no deposition on pristine monolayers. In addition, we show that it is possible to reliably seed the deposition, even on the monolayer, using non-covalent functionalisation with perylene derivatives as anchor unit.
X-Ray Spectrometry, 1990
CdTe and HgCdTe epitaxial layers were grown on 50 mm diameter (100) GaAs wafers in a Quantax 226 metall+ organic chemical vapour deposition system. Dimethylcadmium, diethyl telluride and elemental mercury were used as starting materials in the thermal growth process which takes place in a flow of hydrogen at 250-35O0C. Tbe layers were characterized by (1) an interference contrast microscope for surface morphology; (2) FTIR spectroscopy for compositional and thickness uniformity; (3) x-ray topography and double crystal diffractometry for the nondestructive evaluation of the crystalline quality and microstructure; (4) energydispersive x-ray analysis (WDX/EDX) for compositional studies; (5) transmission electron microscopy for interface observations and analysis; and (6) Rutherford backscattering and channelling analysis for surface stoichiometry and crystal quality determinations.
Recent Developments on the Properties of Chalcogenide Thin Films
Chalcogens [Working Title], 2022
Chalcogenide thin films have attracted a great deal of attention for decades because of their unique properties. The recent developments on thin film-based supercapacitor applications were reported. As a result of sustained efforts, the experimental findings revealed remarkable properties with enhanced fabrication methods. The properties of perovskite solar cells were discussed in terms of crystal structure and phase transition, electronic structure, optical properties, and electrical properties. Perovskite solar cell has gained attention due to its high absorption coefficient with a sharp absorption edge, high photoluminescence quantum yield, long charge carrier diffusion lengths, large mobility, high defect tolerance, and low surface recombination velocity. The thin film-based gas sensors are used for equally the identification and quantification of gases, and hence should be both selective and sensitive to a required target gas in a mixture of gases. Metal chalcogenide materials ...
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 2017
AsS chalcogenide films, where As content is 60-40at.%, have been prepared via a RF non-equilibrium low-temperature argon plasma discharge, using volatile As and S as the precursors. Optical properties of the films were studied in UV-visible-NIR region in the range from 0.2 to 2.5μm. Infrared and Raman spectroscopy have been employed for the elucidation of the molecular structure of the newly developed material. It was established that PECVD films possess a higher degree of transparency (up to 80%) and a wider transparency window (>20μm) in comparison with the "usual" AsS thin films, prepared by different thermal methods, which is highly advantageous for certain applications.
A new method for synthesis of As-Te chalcogenide films
Superlattices and Microstructures, 2017
A novel Plasma Enhanced Chemical Vapor Deposition method for synthesis of amorphous As x Te 100-x (31≤x ≤49) films is demonstrated. The innovative process has been developed in a non-equilibrium low-temperature argon plasma under reduced pressure, employing for the first time volatile As and Te as precursors. Utilization of inorganic precursors, in contrast to the typically used in CVD metal-organic precursors, has given us the chance to achieve сhalcogenide As-Te films of very high quality and purity. Phase and structural evolution of the As-Te system, based on equilibrium coexistence of two phases (AsTe and As 2 Te 3) has been studied. The dependence of structure and optical bandgap of the chalcogenide materials on their composition was established. The newly developed process is cost-effective and enables deposition of As-Te films with a thickness ranging from 10 nm to 10 µm, the latter is highly desireable for one-mode planar waveguides applications and in other components of integral optics.
Properties and limitations of chalcogenide films
Chinese Optics Letters, 2010
Two chalcogenide films with composition Ge 25-x Sb 10 +x S 65 (x = 0, 10) and Te 20 As 30 Se 50 , called 2S1G and TAS, respectively, are studied. These materials have high linear and nonlinear refractive indices and present interesting photosensitive behavior toward bandgap light. Further, these chalcogenides glasses can be deposited in an amorphous thin film for optical coatings or waveguides. Their properties and limitations, including their photoinduction effects, nonlinear Kerr effect, photodiffusion of silver, and aging, are discussed.
Plasma Chemistry and Plasma Processing, 2017
First time the method of plasma-enhanced chemical vapor deposition was used for preparation of As-Te chalcogenide films of different chemical and phase composition. The samples were synthesized via direct interaction of arsenic and tellurium vapors into low-temperature non-equilibrium RF (40 MHz) plasma discharge at reduced pressure (0.1 Torr). The plasma parameters such as temperature and concentration of electrons were measured by moving double probe diagnostic system. The dependence of solid phase radial distribution on plasma characteristics was established. Besides, the phase and structural evolution of As-Te films based on equilibrium coexistence of two phases (AsTe and As 2 Te 3) and implemented by changing of the ratio of the initial substances in gas phase has been studied and discussed.
Fabrication and Characterization of High-Mobility Solution-Based Chalcogenide Thin-Film Transistors
IEEE Transactions on Electron Devices, 2013
Using positive surface charge instead of traditional-ray total dose irradiation, the electric field distribution of a P-channel VDMOS terminal has been analyzed. A novel terminal structure for improving the total dose irradiation hardened of P-channel VDMOS has been proposed, and the structure is simulated and demonstrated with a-150 V P-channel VDMOS. The results show that the peak current density is reduced from 5.51 10 3 A/cm 2 to 2.01 10 3 A/cm 2 , and the changed value of the breakdown voltage is 2.5 V at 500 krad(Si). Especially, using 60 Co and X-ray to validate the results, which strictly match with the simulated values, there is not any added mask or process to fabricate the novel structure, of which the process is compatible with common P-channel VDMOS processes. The novel terminal structure can be widely used in total irradiation hardened P-channel VDMOS design and fabrication, which holds a great potential application in the space irradiation environment.