Lattice Sites of Silicon Impurities in AlGaAs Grown by Liquid Phase Epitaxy

Abstract

Localised vibrational mode infrared absorption (10 K) and Hall measurements were made on a series of Si doped Al xGa1-xAs samples with 0 < x < 0.25 grown by liquid phase epitaxy. Localised vibrational modes were detected from SiGa donors, Sim acceptors and SiGa-SiAs pairs which increased in frequency as x increased. The assignments of new lines observed at 386, 388 and 391 cm -1 are discussed in relation to possible perturbations of the lines from SiG a or SiAs. The presence of DX centres was inferred from observed persistent photoconductivity and attempts were made to relate this result to the presence of the new IR lines.