Institute of Physics, Wroclaw University of Technology, Wroclaw, Poland.
J Phys Condens Matter. 2013 Feb 13;25(6):065801. doi: 10.1088/0953-8984/25/6/065801. Epub 2013 Jan 10.
In this study we apply time resolved photoluminescence and contactless electroreflectance to study the carrier collection efficiency of a GaInNAsSb/GaAs quantum well (QW). We show that the enhancement of photoluminescence from GaInNAsSb quantum wells annealed at different temperatures originates not only from (i) the improvement of the optical quality of the GaInNAsSb material (i.e., removal of point defects, which are the source of nonradiative recombination) but it is also affected by (ii) the improvement of carrier collection by the QW region. The total PL efficiency is the product of these two factors, for which the optimal annealing temperatures are found to be ~700 °C and ~760 °C, respectively, whereas the optimal annealing temperature for the integrated PL intensity is found to be between the two temperatures and equals ~720 °C. We connect the variation of the carrier collection efficiency with the modification of the band bending conditions in the investigated structure due to the Fermi level shift in the GaInNAsSb layer after annealing.
在这项研究中，我们应用时间分辨光致发光和非接触式电反射率来研究 GaInNAsSb/GaAs 量子阱（QW）的载流子收集效率。我们表明，在不同温度下退火的 GaInNAsSb 量子阱的光致发光增强不仅源于（i）GaInNAsSb 材料光学质量的提高（即消除了非辐射复合的点缺陷源），而且还受到（ii）QW 区域载流子收集的改善的影响。总 PL 效率是这两个因素的乘积，最佳退火温度分别约为 700°C 和 760°C，而总 PL 强度的最佳退火温度介于这两个温度之间，约为 720°C。我们将载流子收集效率的变化与由于退火后 GaInNAsSb 层中费米能级的移动而导致所研究结构中的能带弯曲条件的变化联系起来。
