Suppression of hole leakage by adding a hole blocking layer prior to the first quantum barrier in GaN-based near-ultraviolet laser diodes.

Compared with GaN-based visible GaN/InGaN multiple-quantum-well laser diodes (LDs), near-ultraviolet LDs may suffer from a sever hole leakage due to the shallower quantum wells (QWs). Here, a 10 nm n-type AlGaN hole blocking layer (HBL) is proposed to put before the first quantum barrier layer and form a barrier on the valence band to prevent injected holes from leaking into the n-type region. Furthermore, the effect of Al composition of Al xGa1− xN HBL on LD performance is studied. Theoretical analysis is performed by using advanced device simulation. The simulation results show that lower threshold current and higher output power of LD can be obtained when Al composition of Al xGa1− xN HBL is 0.23. This result can be attributed to a dramatically reduced electron and hole leakage, and more stimulated recombination in QWs. [ABSTRACT FROM AUTHOR]