Deep-Hole Traps in p-Type GaAs1-xBix Grown by Molecular Beam Epitaxy

Deep-level transient spectroscopy measurements reveal deep-hole traps with activation energies of 0.43 and 0.23 eV in p-type GaAs 1-x Bi x samples with $x = 1.2$ and 3.4%, respectively, grown at 370 °C by molecular beam epitaxy. In spite of low-temperature growth, the deep-level trap concentration is suppressed on the order of $10^{15}$ cm -3 , suggesting that Bi atoms contribute to the enhancement of migration to prevent the formation of point defects. The possible origin of the hole traps is discussed in connection with arsenic antisite, As \text{Ga , and bismuth antisite, Bi \text{Ga .