A STUDY OF THE ELECTRICAL-PROPERTIES CONTROLLED BY RESIDUAL ACCEPTORS IN GALLIUM ANTIMONIDE

Carrier concentration and mobility were investigated by Hall measurements over a wide temperature range (7-700 K) in nominally undoped p-GaSb grown from the melt. The main parameters relating to levels controlling the conductivity and to scattering mechanisms limiting the mobility were derived by a self-consistent fit of carrier density and moblity versus temperature. In the temperature range 20-500 K an approach using two acceptor levels succesfully explained the temperature variation of the hole density. A negligible influence of non-polar optical phonons resulted from the analysis of the high temperature mobility, whereas an impurity band conduction dominates the electric transport at low temperature. Photoluminescence spectra were measured in the interval 2-300 K to confirm the energy location of the main localized level: by considering a correction factor for the compensation effect, complete agreement between optical and thermal ionization energies was found.