Laser-induced chemical vapor deposition of hydrogenated amorphous silicon: Photovoltaic devices and material properties

Abstract

We report the growth by laser-induced chemical vapor deposition (LICVD) of hydrogenated amorphous silicon p-i-n and n-i-p photovoltaic devices. Properties of the LICVD material and devices were studied by examining the light and dark current density vs. voltage curves and the spectral quantum efficiencies with and without applied reverse bias. We also report steady state photoconductivity measurements of the product of the majority carrier mobility and lifetime in undoped films grown at various substrate temperatures. Although they have less hydrogen and higher neutral dangling bond densities than films grown at lower temperatures, LICVD films grown at a substrate temperature of 400 °C have better photovoltaic and photoconductive properties. Device characterizations show that, in the present geometry, film homogeneity is good along the laser beam axis and extends laterally across a strip 7 mm wide.