Pūkienė S, Karaliūnas M, Jasinskas A, Dudutienė E, Čechavičius B, Devenson J, Butkutė R, Udal A, Valušis G
Department of Optoelectronics, Center for Physical Sciences and Technology, Saulėtekio Av. 3, 10257 Vilnius, Lithuania.
Nanotechnology. 2019 Nov 8;30(45):455001. doi: 10.1088/1361-6528/ab36f3. Epub 2019 Jul 30.
Influence of barrier material and structure on carrier quantum confinement in GaAsBi quantum wells (QWs) is studied comprehensively. Single- and multi-QW structures were grown using solid-state molecular beam epitaxy with conventional rectangular, step-like and parabolically graded AlGaAs barrier designs. It was discovered that room temperature photoluminescence is increased by more than 50 times in the GaAsBi QWs with parabolically graded barriers (PGBs) if compared to standard rectangular and step-like structures. The enhancement of photoluminescence was reproducible within the range of growth parameters. The carrier localization and increase of trapping efficiency in GaAsBi QWs is responsible for observed enhancement in radiative properties of PGB structures. The random potential field fluctuations for carriers were increased up to 44 meV due to the blurred well-barrier interface causing the conditions for Bi content and/or well width variations. Due to the impact of self-organizing effects on the reproducibility of optical properties, the GaAsBi QWs with AlGaAs PGBs open the window for fabrication of 1.0-1.55 μm wavelength emission lasers based on GaAsBi quantum structures.
全面研究了势垒材料和结构对GaAsBi量子阱（QW）中载流子量子限制的影响。采用固态分子束外延生长了单量子阱和多量子阱结构，采用传统的矩形、阶梯状和抛物线渐变AlGaAs势垒设计。研究发现，与标准的矩形和阶梯状结构相比，具有抛物线渐变势垒（PGB）的GaAsBi量子阱在室温下的光致发光增加了50倍以上。在生长参数范围内，光致发光的增强是可重复的。GaAsBi量子阱中载流子的局域化和俘获效率的提高是PGB结构辐射特性增强的原因。由于阱-势垒界面模糊导致Bi含量和/或阱宽度变化的条件，载流子的随机势场波动增加到44 meV。由于自组织效应对光学性质再现性的影响，具有AlGaAs PGB的GaAsBi量子阱为基于GaAsBi量子结构的1.0 - 1.55μm波长发射激光器的制造打开了窗口。
