Suppression of electron and hole overflow in GaN-based near-ultraviolet laser diodes* *Project supported by the Science Challenge Project, China (Grant No. Z2016003), the National Key R & D Program of China (Grant Nos. 2016YFB0400803 and 2016YFB0401801), the National Natural Science Foundation of China (Grant Nos. 61674138, 61674139, 61604145, 61574135, 61574134, 61474142, 61474110, 61377020, and 61376089), and the Beijing Municipal Science

Abstract

In order to suppress the electron leakage to p-type region of near-ultraviolet GaN/In x Ga1–x N/GaN multiple-quantumwell (MQW) laser diode (LD), the Al composition of inserted p-type Al x Ga1–x N electron blocking layer (EBL) is optimized in an effective way, but which could only partially enhance the performance of LD. Here, due to the relatively shallow GaN/In0.04Ga0.96N/GaN quantum well, the hole leakage to n-type region is considered in the ultraviolet LD. To reduce the hole leakage, a 10-nm n-type Al x Ga1–x N hole blocking layer (HBL) is inserted between n-type waveguide and the first quantum barrier, and the effect of Al composition of Al x Ga1–x N HBL on LD performance is studied. Numerical simulations by the LASTIP reveal that when an appropriate Al composition of Al x Ga1–x N HBL is chosen, both electron leakage and hole leakage can be reduced dramatically, leading to a lower threshold current and higher output power of LD.