垂直腔面发射激光器DBR的生长优化

Growth Optimization of Vertical Cavity Surface-Emitting Laser DBR

摘要:

基于能带理论和分布布拉格反射镜(DBR)的工作原理,分析了垂直腔面发射激光器(VCSEL)中DBR串联电阻较大的原因。采用组分渐变降低DBR结构中异质结界面处势垒,优化DBR的各层掺杂浓度,通过调控费米能级进一步降低DBR中的异质结势垒,从而有效降低DBR串联电阻。实验采用Al0.22Ga0.78As/Al0.9Ga0.1As作为生长DBR的两种材料,设计了DBR各层厚度,研究了AlGaAs材料的最佳生长温度,利用MOCVD外延技术完成了795nm VCSEL突变DBR与渐变DBR的生长。经过工艺制备,测得突变DBR和渐变DBR的电阻分别为6.6和5.3Ω,优化生长后的DBR电阻得到有效降低。

Abstract:

Based on the energy band theory and the principle of distributed Bragg mirror (DBR), the reason for the large DBR series resistance in VCSEL was analyzed. The potential barrier at the interface of heterojunction in DBR structure was reduced by component gradient, the doping concentration of each layer of DBR was optimized, and the heterojunction potential barrier in DBR was further reduced by regulating Fermi energy level, thus the series resistance of DBR was effectively reduced. Al0.22Ga0.78As/Al0.9Ga0.1As was used as two materials for DBR growth. The thickness of each layer of DBR was designed and the optimum growth temperature of AlGaAs material was studied. The 795nm VCSEL mutation DBR and gradual DBR were grown by MOCVD epitaxy. The resistance of mutant DBR and gradient DBR was 6.6 and 5.3Ω, respectively. The resistance of DBR after optimized growth was effectively reduced.