Epitaxial growth and optically pumped stimulated emission in AlGaN/InGaN ultraviolet multi-quantum-well structures
Epitaxial growth and optically pumped stimulated emission in AlGaN/InGaN ultraviolet multi-quantum-well structures
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AlGaN/InGaN 紫外多量子阱结构中的外延生长和光泵受激发射
DOI：
10.1007/s11664-019-07932-x
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发表时间：
2020
影响因子：
2.1
通讯作者：
Russell D. Dupuis
中科院分区：
文献类型：
--
作者：
Ping Chen;Young Jae Park;Yuh-Shiuan Liu;Theeradetch Detchprohm;P. Douglas Yoder;Shyh-Chiang Shen;Russell D. Dupuis
实验研究了生长温度对紫外AlGaN/InGaN多量子阱(MQW)界面形态和受激发射的影响。在MOCVD外延生长AlGaN/InGaN多量子阱的过程中，InGaN量子阱(QW)的温度从较低温度到AlGaN量子垒(QBS)的斜率故意从1.0℃/S变化到4.0℃/S。原子力显微镜图像显示，当生长温度上升到AlGaN量子垒的设定值时，InGaN量子阱的表面形貌因热效应而变化。受激发射结果表明，多量子阱的阈值抽运功率密度随温度斜率从1.0°C/S增加到3.0°C/S而减小，当斜率为4.0°C/S时，阈值抽运功率密度略有增加，这可能是由于温度斜率阶跃过程中的热退化效应所致。长时间的高温退火会降低InGaN量子线中富铟微结构的密度和相应的局域态密度，这可能是导致InGaN量子线中辐射复合的原因。由于AlGaN层和InGaN层的最佳生长温度相差很大，较高的斜率将更适合于紫外光AlGaN/InGaN多量子阱的生长。
The thermal effect of the growth temperature on interface morphology and stimulated emission in ultraviolet AlGaN/InGaN multiple quantum wells (MQWs) are experimentally investigated. During the MOCVD epitaxial growth of AlGaN/InGaN MQWs, the ramping rate from a lower temperature for InGaN quantum wells (QWs) to a higher one for AlGaN quantum barriers (QBs) is intentionally changed from 1.0°C/s to 4.0°C/s. Atomic force microscopy images show that the surface morphology of InGaN QWs, which is improved by a thermal effect when the growth temperature rises to the set value of the AlGaN QBs, varies with different temperature ramping rates. The results of stimulated emission indicate that the threshold pumping power density of MQWs is decreased with increasing temperature ramping rate from 1.0°C/s to 3.0°C/s and then slightly increased when the ramping rate is 4.0°C/s. This phenomenon is believed to result from the thermal degradation effect during the temperature ramp step. A long-time high-temperature annealing will reduce the density of indium-rich microstructures as well as the corresponding localized state density, which is assumed to contribute to the radiative recombination in the InGaN QWs. Given the great difference between optimal growth temperatures for AlGaN and InGaN layers, a higher ramping rate would be more appropriate for the growth of ultraviolet AlGaN/InGaN MQWs.