Study of MnAs as a spin injector for GaAs-based semiconductor heterostructures

We report studies of two key factors involved in the use of MnAs as a spin injector, namely, Mn diffusion and spin injection properties when it is grown on GaAs-based semiconductor heterostructures. Depth profile of Mn concentration in a sample consisting of a MnAs film grown on GaAs is investigated with time-of-flight secondary ion mass spectroscopy. The result shows that Mn diffusion into GaAs is negligible, unlike the case of Ga1−x Mn x As/GaAs, in which Mn diffusion is significant. Meanwhile, robust spin injection is observed with MnAs as a spin injector for a GaAs-based light emitting diode, persisting up to room temperature.