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 naturalp‐type doping of the layers is limited by the thermal acceptors ( p∼4×1016cm−3) and the lowest reproducible uniform electron concentration obtained by Te compensation isn∼1016cm−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 ofn‐type GaAlSb. Some parameters can be deduced from the various characterizations: the carrier lifetime in the space‐charge region of Zn‐diffusedp+/njunctions, &tgr;∼3×10−10s; electron diffusion lengths in the as‐grown Ga0.96Al0.04Sb layer,Ln=5 &mgr;m, and in the Zn‐diffused layer,Ln=1.5 &mgr;m; and the hole diffusion length in then‐compensated layers,Lp=1 &mgr;m.