Epi-n-IZO thin films/1 0 0 Si, GaAs and InP by L-MBE -: a novel feasibility study for SIS type solar cells

High quality epitaxial indium zinc oxide (heavily indium oxide doped) (epi-n-IZO) thin films were optimized by laser-molecular beam epitaxy (L-MBE) i.e., pulsed laser deposition (PLD) technique for fabricating novel iso- and hetero-semiconductor insulator semiconductor (SIS) type solar cells using Johnson Matthey "specpure"- grade 90% In2O3 mixed 10% ZnO (as commercial indium tin oxide (ITO) composition) pellets. The effects of substrate temperatures, substrates and heavy indium oxide incorporation on IZO thin film growth, opto-electronic properties with <1 0 0> silicon (Si), gallium arsenide (GaAs) and indium phosphide (InP) wafers were studied. As well as the feasibility of developing some novel models of iso- and hetero-SIS type solar cells using epi-IZO thin films as transparent conducting oxides (TCOs) and <100> oriented Si, GaAs and InP wafers as base substrates was also studied simultaneously. The optimized films were highly oriented, uniform, single crystalline approachment, nano-crystalline, anti-reflective (AR) and epitaxially lattice matched with (10 0) Si, GaAs and InP wafers without any buffer layers. The optical transmission T (max) greater than or equal to 95% is broader and absolute rivals that of other TCOs such as ITO. The highest conductivity observed is sigma = 0.47 x 10(3) Omega(-1) cm(-1) (n-type), carrier density n = 0. 168 x 10(20) cm(-3) and mobility mu = 123 cm(2)/V s. From optoelectronic characterizations, the solar cell characteristics and feasibilities of fabricating respective epi-n-TCO/<1 0 0> wafer SIS type solar cells were confirmed. Also, the essential parameters of these cells were calculated and tabulated. We hope that these data be helpful either as a scientific or technical basis in semiconductor processing. (C) 2004 Elsevier Ltd. All rights reserved.