The effect of electron blocking layer on the performance of MQW oxide-confined intracavity-contacted InGaN-based vertical cavity surface emitting lasers

Abstract

The effects of inserting AlGaN electron blocking layer (EBL) in the GaN-based vertical cavity surface emitting laser (VCSEL) structures on the LD performance has been investigated by Integrated System Engineering Technical Computer Aided Design (ISE TCAD) program software. The simulation results indicated that the performance characteristics of GaN-based quantum-well VCSEL were improved when the AlGaN EBL has been added. The effect of Al mole fraction (x) of the AlxGa1−xN EBL on the GaN-based VCSEL performance ranging from x=0.15 to x=0.25 was also studied. At x=0.15 to x=0.17, the threshold current was reduced. This reduction in the threshold current is due to the increase in the carrier confinement which is achieved by accumulated much more carrier close to the active region caused by the added AlxGa1−xN EBL. Above the x=0.17, the threshold current was increased which is attributed to the saturation of the carriers inside the active region that leads to increase in the leakage current. It also was due to that the EBL obstacle the hole flowing in the active region in the x>0.17. GaN-based VCSEL had the optimum performance with Al0.17Ga0.83N EBL; therefore, the effect of Al0.17Ga0.83N EBL thickness on the GaN-based quantum well VCSEL performance has also been investigated. According to the simulation results, the GaN-based VCSEL had the optimum performance when the EBL thickness was 25nm.