Title :
Photo-assisted CVD of a-Si:H solar cells and a-SiGe:H films
Author :
Hegedus, S.S. ; Rocheleau, R.E. ; Tullman, R.M. ; Albright, D.E. ; Saxena, N. ; Buchanan, W.A. ; Schubert, K.E. ; Dozier, R.
Author_Institution :
Inst. of Energy Conversion, Delaware Univ., Newark, DE, USA
Abstract :
High-efficiency (10%) a-Si solar cells and promising a-SiGe-H alloy films have been deposited by mercury-sensitized photochemical vapor deposition. Alloy films were prepared from mixtures of SiH4, Si2H6, GeH4, He, and H2. The effects of gas composition and substrate temperature on film composition, H2 bonding, and optoelectronic properties are reported. Silicon dihydride bonding is shown to decrease with increasing deposition temperature. A maximum in the ratio of dihydride to monohydride absorption peaks occurs at about 60% Ge. Preferential attachment of H to Si increases with Ge content. It is essential to minimize dihydride bonding to obtain good optoelectronic properties. Hole properties (Lp and Eu) show much less dependence than electron properties (photoconductivity and conduction band tail) on Ge content for 1.4-eV films.
Keywords :
Ge-Si alloys; amorphous semiconductors; chemical vapour deposition; elemental semiconductors; hydrogen; semiconductor growth; semiconductor thin films; silicon; solar cells; H2; He; Si:H; SiGe:H; bonding; conduction band tail; electron properties; gas composition; hole properties; mercury-sensitized photochemical vapor deposition; photoconductivity; semiconductor; substrate temperature; Absorption; Bonding; Chemical vapor deposition; Helium; Photochemistry; Photovoltaic cells; Semiconductor films; Silicon alloys; Substrates; Temperature;
Conference_Titel :
Photovoltaic Specialists Conference, 1988., Conference Record of the Twentieth IEEE
Conference_Location :
Las Vegas, NV, USA
DOI :
10.1109/PVSC.1988.105672
