Lattice strain fromDXcenters and persistent photocarriers in Sn-doped and Si-dopedGa1−xAlxAs

The lattice strain caused by electron emission from DX centers was determined by x-ray diffraction for Sn-doped and Si-doped Ga 1-x Al x As, with x Al =0.22-0.24. Measurements were made after cooling samples to 14 K in the dark, which filled DX centers and thereby produced low conductivity. The measurements were repeated after emptying the DX centers by ir illumination, giving ΔN e =(1.0-1.6)×10 18 cm -3 conduction electrons which persisted after illumination