MOCVD of Bi2Te3 and Sb2Te3 on GaAs Substrates for Thin-Film Thermoelectric Applications

2006 ◽  
Vol 6 (11) ◽  
pp. 3325-3328 ◽  
Author(s):  
Jeong-Hun Kim ◽  
Yong-Chul Jung ◽  
Sang-Hee Suh ◽  
Jin-Sang Kim
Keyword(s):  
Thin Film ◽  
Carrier Concentration ◽  
Deposition Temperature ◽  
Growth Parameters ◽  
Chemical Vapour ◽  
Thermoelectric Device ◽  
Organic Chemical ◽  
Gaas Substrates ◽  
Metal Organic ◽  
Surface Morphologies

Metal organic chemical vapour deposition (MOCVD) has been investigated for growth of Bi2Te3 and Sb2Te3 films on (001) GaAs substrates using trimethylbismuth, triethylantimony and diisopropyltelluride as metal organic sources. The surface morphologies of Bi2Te3 and Sb2Te3 films were strongly dependent on the deposition temperatures as it varies from a step-flow growth mode to island coalescence structures depending on deposition temperature. In-plane carrier concentration and electrical Hall mobility were highly dependent on precursor ratio of VI/V and deposition temperature. By optimizing growth parameters, we could clearly observe an electrically intrinsic region of the carrier concentration over the 240 K in Bi2Te3 films. The high Seebeck coefficient (of −160 μVK−1 for Bi2Te3 and + 110 μVK−1 for Sb2Te3 films, respectively) and good surface morphologies of these materials are promising for the fabrication of a few nm thick periodic Bi2Te3/Sb2Te3 super lattice structures for thin film thermoelectric device applications.

High Mobility ZnO thin film transistors using the novel deposition of high-k dielectrics

2011 ◽  
Vol 1315 ◽  
Author(s):  
D. K. Ngwashi ◽  
R. B. M. Cross ◽  
S. Paul ◽  
Andrian P. Milanov ◽  
Anjana Devi
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Performance Metrics ◽  
Chemical Vapour ◽  
High Mobility ◽  
Hafnium Dioxide ◽  
Organic Chemical ◽  
Channel Mobility ◽  
High K ◽  
Metal Organic

ABSTRACTIn order to investigate the performance of ZnO-based thin film transistors (ZnO-TFTs), we fabricate devices using amorphous hafnium dioxide (HfO2) high-k dielectrics. Sputtered ZnO was used as the active channel layer, and aluminium source/drain electrodes were deposited by thermal evaporation, and the HfO2 high-k dielectrics are deposited by metal-organic chemical vapour deposition (MOCVD). The ZnO-TFTs with high-k HfO2 gate insulators exhibit good performance metrics and effective channel mobility which is appreciably higher in comparison to SiO2-based ZnO TFTs fabricated under similar conditions. The average channel mobility, turn-on voltage, on-off current ratio and subthreshold swing of the high-k TFTs are 31.2 cm2V-1s-1, -4.7 V, ~103, and 2.4 V/dec respectively. We compared the characteristics of a typical device consisting of HfO2 to those of a device consisting of thermally grown SiO2 to examine their potential for use as high-k dielectrics in future TFT devices.

Analysis of Faceted Growth Hillocks in MOCVD Grown Epitaxial HgCdTe on GaAs with a Nuclear Microprobe

1991 ◽  
Vol 238 ◽  
Author(s):  
David N. Jamieson ◽  
S. P. Dooley ◽  
S. P. Russo ◽  
P. N. Johnston ◽  
G. N. Pain ◽  
...  
Keyword(s):  
Chemical Vapour ◽  
Normal Growth ◽  
Areal Density ◽  
Growth Conditions ◽  
Organic Chemical ◽  
Epitaxial Layers ◽  
Nuclear Microprobe ◽  
Growth Defects ◽  
Gaas Substrates ◽  
Metal Organic

ABSTRACTHg1-xCdxTe epitaxial layers on GaAs substrates grown by Metal Organic Chemical Vapour Deposition (MOCVD) display growth defects resembling pyramidal faceted hillocks which appear to originate from defects originally present on the substrate. For <100> oriented GaAs substrates and normal growth conditions, these growth defects have an areal density of 1–1000 mm-2. The size of the hillocks depends on the layer thickness and they have the potential to degrade performance of optoelectronic devices fabricated in the epitaxial layers. Nuclear microprobe analysis, performed with a 2 MeV He+ beam focused to less than 5 μm in diameter, has allowed the hillocks to be imaged with the technique of Channeling Contrast Microscopy (CCM). Channeling spectra, obtained by Rutherford Backseat tering Spectrometry (RBS) of the hillocks themselves, showed that the χmin was 13 %. This was similar to the χmin of the high quality single crystal surrounding material. The CCM images also revealed extensive regions of poor channeling, with shapes that suggested that the regions originally arose from scratches in the substrate. These poor channeling regions were not readily observable by other techniques.

scholarly journals Metal-organic chemical vapour deposition of lithium manganese oxide thin films via single solid source precursor

2015 ◽  
Vol 33 (4) ◽  
pp. 725-731 ◽  
Author(s):  
K.O. Oyedotun ◽  
E. Ajenifuja ◽  
B. Olofinjana ◽  
B.A. Taleatu ◽  
E. Omotoso ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Lithium Manganese Oxide ◽  
Organic Chemical ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lithium Manganese ◽  
Metal Organic

AbstractLithium manganese oxide thin films were deposited on sodalime glass substrates by metal organic chemical vapour deposition (MOCVD) technique. The films were prepared by pyrolysis of lithium manganese acetylacetonate precursor at a temperature of 420 °C with a flow rate of 2.5 dm3/min for two-hour deposition period. Rutherford backscattering spectroscopy (RBS), UV-Vis spectrophotometry, X-ray diffraction (XRD) spectroscopy, atomic force microscopy (AFM) and van der Pauw four point probe method were used for characterizations of the film samples. RBS studies of the films revealed fair thickness of 1112.311 (1015 atoms/cm2) and effective stoichiometric relationship of Li0.47Mn0.27O0.26. The films exhibited relatively high transmission (50 % T) in the visible and NIR range, with the bandgap energy of 2.55 eV. Broad and diffused X-ray diffraction patterns obtained showed that the film was amorphous in nature, while microstructural studies indicated dense and uniformly distributed layer across the substrate. Resistivity value of 4.9 Ω·cm was obtained for the thin film. Compared with Mn0.2O0.8 thin film, a significant lattice absorption edge shift was observed in the Li0.47Mn0.27O0.26 film.

MOCVD of CuInE2 (Where E = S or Se) and Related Materials for Solar Cell Devices

1999 ◽  
Vol 606 ◽  
Author(s):  
Michael Kemmler ◽  
Michael Lazell ◽  
Paul O'brien ◽  
David J. Otwaya
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Organic Chemical ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Organic ◽  
Scanning Electron

AbstractThin film(s) of chalcopyrite CuInE2(where E = S or Se) have been grown by low-pressure metal-organic chemical vapour deposition (LP-MOCVD) using the precursors [In(E2CNMenHexyl)3] and [Cu(E2CNMenHexyl)2]. Similarly, thin films of ME (where M = Zn, Cd; E = S, Se) have been deposited from precursors of general formula [M(E2CNMenHex)2]x. Films were grown on glass between 400 - 500 °C, and characterized by X-ray diffraction, optical spectroscopy (UV/Vis), EDAX and scanning electron microscopy.

The Effects of Deposition temperature on the Growth of Copper films produced by low pressure metal-organic chemical vapour deposition

1995 ◽  
Vol 391 ◽  
Author(s):  
S.S. Yoon ◽  
S.W. Kang ◽  
S.S. Chun
Keyword(s):  
Chemical Vapour Deposition ◽  
Deposition Temperature ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Low Pressure ◽  
Organic Chemical ◽  
Copper Films ◽  
Cross Sectional ◽  
Initial Stage ◽  
Metal Organic

AbstractCopper was deposited onto TiN by low pressure metal-organic chemical vapour deposition, using hfacCu(I)TMVS and argon carrier gas. The effects of the deposition temperature on the growth of copper films were investigated by observing the surface morphology and the cross sectional morphology of copper films. At the initial stage of growth, copper films tended to have the island-like growth mode, irrespective of the deposition temperatures. It was also observed that the aspect ratio(=height to width) of the islands gradually increased as the deposition temperature increased. The poorer movability of the copper atoms at the higher deposition temperature was evaluated on the basis of hindering effect by the following copper deposits.

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