Forward current-voltage characteristics and reverse recovery of high-voltage p–i–n diodes based on AlxGa1–xAs1–ySby layers with x ranging from 0 to 0.6 and y ranging from 0 to 0.2, manufactured by liquid-phase epitaxy due to self-doping with background impurities, have been studied. The forward current-voltage characteristics, described as a sum of the recombination current in the space charge region and the diffusion current in the base, have been  observed at low current densities for p0–i–n0 junctions of GaAs, AlxGa1–xAs and AlxGa1–xAs1–ySby with x up to 0.6 and y up to 0.04. The effective lifetime of nonequilibrium charge carriers decreases from ~ 170 ns in GaAs layers to  30–60 ns in the layers of AlxGa1–xAs with x ranging from 0.2 to 0.45 and to 4–12 ns in AlxGa1–xAs1–ySby layers.