ODmr Investigations ofGe Acceptors in p-Type Al sub 0.4Ga sub 0.6As

摘要

P-Type Ge-doped Al sub 0.4Ga sub 0.6As layers grown by liquid Phase epitaxy have bee nstudied with near infrared optical absorpton and electron parmagnetci resonance detected via the magnetic circular dichrism of the absorption. A broad MCDA band has been observed in the same spectral region ad a photolionization absorption band. The MCDA-EPR spectrum reveasled an anisotropic and asymmetric line with a g-factor for B [100], a half width deltaB sub 1/2=60mT, a spin-lattice relaxation time T sub 1(1.5K)=5+ and -2ms and S=1/2. The anisotropy of the MCDA-EPR line shows that the symmetry is lower than tetrahedral. In addition, we observed a second weaker EPR line, with a very short T sub 1 at 1.5K and an naomalously broadend linewidth. For the origin of these two defects we propose a model in which the neutral. Paramagnetic Ge-acceptro induces either shallow EMT or deep levels. While the deep acceptor has its symetry lowered by the alloy disorder, the shaalow level is thought to be equivalent to the Ge acceptor in GaAs.'