Liquid‐phase‐epitaxial growth of Ga_0.96Al_0.04Sb: Electrical and photoelectrical characterizations

Ga_0.96Al_0.04Sb 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 Ga_0.96Al_0.04Sb layer, L_n=5 μm, and in the Zn‐diffused layer, L_n=1.5 μm; and the hole diffusion length in the n‐compensated layers, L_p=1 μm.