High-resistivity GaSb grown by molecular-beam epitaxy

GaSb undoped layers grown by molecular-beam epitaxy on GaSb or on semi-insulating GaAs substrates at temperatures between 600 and 630 °C are shown to have carrier concentrations in the low 1013 cm−3 range, corresponding to almost intrinsic conditions. The materials have been characterized using current-voltage, capacitance-voltage, Hall effect, photoluminescence, thermally stimulated current, and secondary-ion mass spectrometry. Bulk GaSb (n type) is also found to have converted to high-resistance p type after a heat treatment at 630 °C. Speculations are offered for the responsible mechanism, but a definitive explanation does not exist at this time.