Thin-Film Polycrystalline Ga1-xInxSb Materials

Polycrystalline Ga1-xInxSb thin films with 0<x<1 have been grown on 7059 Corning glass by evaporation from the elemental sources. X-ray diffraction data reveal single-phase materials with cubic structure (space group F ..hivin..4 3 m). The addition of In to the GaSb matrix results in an increase in lattice parameter and consequently a reduction in optical bandgap. Also, increased In content inthe films produces a change in the preferred orientation on films grown on bare 7059 glass. In this contribution, materials of interest are limited to those with optical bandgaps between 0.7 and 0.5 eV. The as-deposited, near-stoichiometry films with Sb/(In+Ga)</=1 show p-type electrical conductivity. Addition of small amounts of Sn provides an effective extrinsic doping effect. In thismaterial, Sn behaves amphoterically providing both donor and acceptor states depending on which element is substituted. Sn incorporation in materials with Sb/(In+Ga)>1 show n-type conductivity.