Amorphous Silicon—Germanium Deposited by Photo—CVD

1985 ◽  
Vol 49 ◽  
Author(s):  
H. Itozaki ◽  
N. Fujita ◽  
H. Hitotsuyanagi
Keyword(s):  
Solar Cell ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Silicon Germanium ◽  
Chemical Vapor ◽  
High Quality ◽  
Transmission Electron ◽  
Amorphous Silicon Germanium ◽  
Hydrogenated Amorphous ◽  
Gas Ratio

AbstractHydrogenated amorphous silicon germanium (a—SiGe:H) films were deposited by photo—chemical vapor deposition (Photo—CVD) of SiH4 and GeH4 with mercury sensitizer. Their band gap was controlled from 0.9 eV to 1.9 eV by changing the gas ratio of SiH4 and GeH4. High quality opto—electrical properties have been obtained for thea—SiGe:H films by Photo—CVD. Hydrogen termination and microstructure of a-SiGe:H were investigated by infrared absorption and transmission electron microscopy. Ana—Si:H solar cell and an a—Si:H/a—SiGe:H stacked solar cell were made, each of which has conversion efficiency 5.3% and 5.1%, respectively.

Hydrogenated Amorphous Silicon Germanium Alloys Grown by the Hot-Wire Chemical Vapor Deposition Technique

1998 ◽  
Vol 507 ◽  
Author(s):  
Brent P. Nelson ◽  
Yueqin Xu ◽  
D.L. Williamson ◽  
Bolko Von Roedern ◽  
Alice Mason ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Silicon Germanium ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
Hot Wire ◽  
Germanium Content ◽  
Amorphous Silicon Germanium ◽  
Hydrogenated Amorphous ◽  
Gas Ratio

ABSTRACTWe successfully grow high-quality hydrogenated amorphous-silicon-germanium alloys (a-SiGe:H) by the hot-wire chemical-vapor deposition (HWCVD) technique using silane and germane gas mixtures. These alloys display electronic properties as good as those grown by the plasma-enhanced chemical-vapor deposition (PECVD) technique, when comparing materials with the same optical bandgaps. However, we grow materials with good electrical properties at high deposition rates—up to 40 Å/s, compared to 1–4 Å/s for PECVD materials. Our alloys exhibit similar trends with increasing Ge content to alloys grown by PECVD. The defect density, the dark conductivity, and the degree of nanostructural heterogeneity (as measured by small-angle X-ray scattering) all increase with increasing germanium content in the alloy. The nanostructural heterogeneity displays a sharp transition between 9 at.% and 14 at.% germanium. PECVD- grown a-SiGe:H alloys exhibit a similar transition at 20 at.% Ge. The photoconductivity and the ambipolar diffusion length of the alloys decrease with increasing germanium content. For a fixed silane-to-germane gas ratio, all material properties improve substantially when increasing substrate temperature (Tsub) from 220°C to 375°C. Increasing Tsub also narrows the optical bandgap and lowers the hydrogen content in the alloys for the same germane-to-silane gas ratio.

Effect of Ge Incorporation on Hydrogenated Amorphous Silicon Germanium Thin Films Prepared by Plasma Enhanced Chemical Vapor Deposition

2012 ◽  
Vol 569 ◽  
pp. 27-30
Author(s):  
Bao Jun Yan ◽  
Lei Zhao ◽  
Ben Ding Zhao ◽  
Jing Wei Chen ◽  
Hong Wei Diao ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Silicon Germanium ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Amorphous Silicon Germanium ◽  
Hydrogenated Amorphous

Hydrogenated amorphous silicon germanium thin films (a-SiGe:H) were prepared via plasma enhanced chemical vapor deposition (PECVD). By adjusting the flow rate of GeH4, a-SiGe:H thin films with narrow bandgap (Eg) were fabricated with high Ge incorporation. It was found that although narrow Eg was obtained, high Ge incorporation resulted in a great reduction of the thin film photosensitivity. This degradation was attributed to the increase of polysilane-(SiH2)n, which indicated a loose and disordered microstructure, in the films by systematically investigating the optical, optoelectronic and microstructure properties of the prepared a-SiGe:H thin films via transmission, photo/dark conductivity, Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR) measurements. Such investigation provided a helpful guide for further preparing narrow Eg a-SiGe:H materials with good optoelectronic properties.

Properties of Catalytic-Cvd Amorphous Silicon-Germanium (a-SiGe:H)

1990 ◽  
Vol 192 ◽  
Author(s):  
Hideki Matsumura ◽  
Masaaki Yamaguchi ◽  
Kazuo Morigaki
Keyword(s):  
Amorphous Silicon ◽  
Silicon Germanium ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
Characteristic Energy ◽  
Optical Band Gaps ◽  
Spin Resonance ◽  
Amorphous Silicon Germanium ◽  
Conductive Properties ◽  
Hydrogenated Amorphous

ABSTRACTHydrogenated amorphous silicon-germanium (a-SiGe:H) films are prepared by the catalytic chemical vapor deposition (Cat-CVD) method using a SiH4, GeH4 and H4 gas mixture. Properties of the films are investigated by the photo-thermal deflection spectroscopy (PDS) and electron spin resonance (ESR) measurements, in addition to the photo-conductive and structural studies. It is found that the characteristic energy of Urbach tail, ESR spin density and other photo-conductive properties of Cat-CVD a-SiGe:H films with optical band gaps around 1.45 eV are almost equivalent to those of the device quality glow discharge hydrogenated amorphous silicon (a-Si:H).

High Quality Amorphous Silicon Prepared by Catalytic Chemical Vapor Deposition (CTL-CVD) Method

1987 ◽  
Vol 95 ◽  
Author(s):  
Hideki Matsumura
Keyword(s):  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Optical Band Gap ◽  
Chemical Vapor ◽  
Catalytic Reactions ◽  
Gas Mixture ◽  
High Quality ◽  
Phosphorus Doping ◽  
Cvd Method ◽  
Hydrogenated Amorphous

AbstractA new method of producing high quality hydrogenated amorphous silicon (a-Si:H) and its compound films is presented. An SiH4 and H2 gas mixture is decomposed without using any plasmas or photochemical excitation, but using only thermal and catalytic reactions between deposition gas and a heated tungsten catalyzer. Photoconductivity of a-Si:H films produced by, this method reaches 10−3 (Ωcm)−1 and photosensitivity exceeds 105 for illumination of AM-1 light of 100 mW/cm2, highly efficient boron- or phosphorus-doping into the films is achieved, and also the optical band gap of the films is easily controlled without apparent degradation of the properties by adding GeH4 gas to the deposition gas.

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