P-TYPE DOPING OF GALLIUM ANTIMONIDE GROWN BY MOLECULAR-BEAM EPITAXY USING SILICON

We report the first effective p-type doping of molecular beam epitaxy (MBE) grown GaSb using silicon. The samples were grown by molecular beam epitaxy and characterized by Hall-effect measurements and photoluminescence. Room-temperature hole concentrations ranging from 4.0×1015 to 4.3×1018 cm-3 were obtained. Photoluminescence (PL) spectra undergo considerable broadening with increasing doping concentration, consistent with an impurity banding picture. Furthermore, the MBE-grown samples display only one of the two PL features found in a melt-grown substrate and no other satellites, suggesting higher material purity. This may be a direct benefit from the use of an antimony cracker, ultrahigh vacuum conditions, and high-purity elemental sources. The short-period strained-layer superlattice buffering scheme employed may have also contributed to better structural quality.