Inelastic tunneling in (111) oriented AlAs/GaAs/AlAs double-barrier heterostructures

AlAs/GaAs/AlAs double-barrier heterostructures grown along the (111) crystal axis show a factor of two improvement in the peak-to-valley ratio compared to samples grown in the (100) orientation. A structure consisting of 2.8 nm barriers and an 8 nm well shows a peak-to-valley ratio much better than any published results on (100) oriented structures with similar well and barrier layers. This result is interpreted in terms of the increased effective mass for carriers tunneling inelastically via the AlAs X-point barrier. An increased mass leads to a reduction in the barrier transmission probability and, therefore, a decrease in the leakage current due to inelastic tunneling.