High peak-to-valley current ratio In 0.22 Ga 0.78 As/AlAsRTDs on GaAsusing relaxed In x Ga ₁₋ x As buffers

The authors have grown In0.22Ga0.78As/AlAs resonant tunnelling diodes (RTDs) on relaxed InxGa1-xAs buffers on GaAs substrates, which show the largest peak-to-valley current ratio (PVCR), 13:1, ever reported for GaAs-based RTDs. X-ray diffraction and photoluminescence (PL) studies confirm the composition and relaxation of the buffers. The intrinsic device performance is excellent despite the presense of some dislocations in the active layers. However, it appears that the relaxed buffers do add series resistance to the intrinsic device.