Enhanced Emission Efficiency of Deep Ultraviolet Light-Emitting AlGaN Multiple Quantum Wells Grown on an N-AlGaN Underlying Layer

Remarkably enhanced light emission efficiency of AlGaN multiple quantum wells (MQWs) was realized by growing on an n-AlGaN underlying layer (UL). The parasitic peaks emitting from inactive regions can be effectively suppressed, and the nonradiative recombination process in AlGaN MQWs proved to be substantially lessened with the inclusion of the n-AlGaN UL. Numerical simulations showed that the electric field in AlGaN MQWs was reduced by 26%, which efficiently weakened the quantum-confined Stark effect (QCSE). Further analysis attributed this to the reduction of strain-induced piezoelectric electric field in the AlGaN well layer. The enhanced emission efficiency of AlGaN MQWs was therefore due to the greatly suppressed nonradiative recombination and reduced QCSE with the introduction of the n-AlGaN UL. The present research will be helpful to the future promotion of high-performance deep ultraviolet (DUV) optoelectronic devices, as well as to better understanding the recombination mechanism in AlGaN MQWs.