Investigation of the mechanism of carrier recombination in GaN-based blue laser diodes before lasing

Abstract

The carrier recombination behaviour of GaN-based blue laser diodes (LDs) is studied and analysed by experiments and simulation calculation before lasing, especially the role of Auger recombination. It is found that Auger recombination plays a crucial role on the decrease of differential efficiency and threshold current of GaN-based blue LDs. The theoretical calculation results show that a large Auger recombination rate may lead to a dominant recombination channel before lasing, which could exceed the radiation recombination and result in an obvious decrease of the differential efficiency. Such a high Auger recombination will dissipate a large number of carriers in the quantum well, resulting in deterioration of device performance, a higher threshold current and a lower efficiency. This work presents a method to evaluate the Auger recombination through the differential efficiency, and also give a clue that suppressing auger recombination rate is beneficial to improve the performance of blue LDs.