Liquid-phase-epitaxial growth of Ga0.96Al0.04Sb: Electrical and photoelectrical characterizations

Abstract

Ga0.96Al0.04Sb layers have been grown by liquid-phase epitaxy on GaSb substrates at 400, 450, and 550 °C. The 450 °C growth leads to the best control of the layer’s quality. At 450 °C the natural p-type doping of the layers is limited by the thermal acceptors ( p∼4×1016 cm−3) and the lowest reproducible uniform electron concentration obtained by Te compensation is n∼1016 cm−3. Electrical and photoelectrical properties of Schottky diodes and mesa Zn-diffused homojunctions realized on these layers are described. They are strongly affected by surface effects attributed to the band bending of n-type GaAlSb. Some parameters can be deduced from the various characterizations: the carrier lifetime in the space-charge region of Zn-diffused p+/n junctions, τ∼3×10−10 s; electron diffusion lengths in the as-grown Ga0.96Al0.04Sb layer, Ln=5 μm, and in the Zn-diffused layer, Ln=1.5 μm; and the hole diffusion length in the n-compensated layers, Lp=1 μm.