利用深能级瞬态谱(DLTS)研究了气源分子束外延(GSMBE)生长的InP1-xBix材料中深能级中心的性质。在未有意掺杂的InP中测量到一个多数载流子深能级中心E1,E1的能级位置为Ec-0.38 e V,俘获截面为1.87×10^(-15)cm^2。在未有意掺杂的InP0.9751Bi0.0249中测量到一个少数载流子深能级中心H1,H1的能级位置为Ev+0.31 eV,俘获截面为2.87×10^(-17)cm^2。深中心E1应该起源于本征反位缺陷PIn,深中心H1可能来源于形成的Bi原子对或者更复杂的与Bi相关的团簇。明确这些缺陷的起源对于InPBi材料在器件应用方面具有重要的意义。
首次提出并实现了一种利用笼式共轴系统搭建的Littman结构平移透镜外腔半导体激光器。通过微调节架驱动准直透镜平移从而改变光栅表面的激光入射角,可以实现约8.5 nm的连续波长调谐,准直透镜平移1μm波长改变约0.02 nm,实验测量值与理论计算值能够很好地吻合。通过压电陶瓷驱动准直透镜平移,研究了Littman结构平移透镜外腔半导体激光器的跳模特性并定性分析了发生跳模的基本原理。此外,该外腔系统的出射激光具有优异的单模特性和稳定性,室温下工作电流为300 m A时单模输出功率超过18 m W。
We investigate InAs/GaAs quantum dot （QD） lasers grown by gas source molecular beam epitaxy with different growth temperatures for InAs dot layers. The same laser structures are grown, but the growth temperatures of InAs dot layers are set as 425 and 500℃, respectively. Ridge waveguide laser diodes are fabricated, and the characteristics of the QD lasers are systematically studied. The laser diodes with QDs grown at 425 ~C show better performance, such as threshold current density, output power, internal quantum efficiency, and characteristic temperature, than those with QDs grown at 500℃. This finding is ascribed to the higher QD density and more uniform size distribution of QDs achieved at 425℃.
