Determining the nature of excitonic dephasing in high-quality GaN/AlGaN quantum wells through time-resolved and spectrally resolved four-wave mixing spectroscopy
Determining the nature of excitonic dephasing in high-quality GaN/AlGaN quantum wells through time-resolved and spectrally resolved four-wave mixing spectroscopy
复制标题
通过时间分辨和光谱分辨四波混合光谱确定高质量 GaN/AlGaN 量子阱中激子相移的性质
DOI：
10.1103/physrevb.96.041303
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发表时间：
2017
影响因子：
3.7
通讯作者：
P. Gilliot
中科院分区：
文献类型：
--
作者：
M. Gallart;M. Ziegler;O. Crégut;E. Feltin;J. Carlin;R. Butté;N. Grandjean;B. Hönerlage;P. Gilliot
应用四波混频光谱的高品质的GaN/AlGaN单量子阱，我们报告的实验测定激子退相时间在不同的温度和激子密度在III族氮化物异质结。通过比较退相和自旋弛豫速率随温度的演化，我们得出结论，这两个过程都与激子碰撞的速率有关。当自旋弛豫发生在运动窄化制度，它保持恒定的大的温度范围内的自旋进动频率随温度线性增加，从而补偿所观察到的失相时间的减少。从这些测量中，推断出在$T= 10\phantom {\rule{0.16em}{0 ex}}\mathrm{K}$处的电子-空穴交换相互作用强度为0.45 meV。
Applying four-wave mixing spectroscopy to a high-quality GaN/AlGaN single quantum well, we report on the experimental determination of excitonic dephasing times at different temperatures and exciton densities in III-nitride heterostructures. By comparing the evolution with the temperature of the dephasing and the spin-relaxation rate, we conclude that both processes are related to the rate of excitonic collisions. When spin relaxation occurs in the motional-narrowing regime, it remains constant over a large temperature range as the spin-precession frequency increases linearly with temperature, hence compensating for the observed decrease in the dephasing time. From those measurements, a value of the electron-hole exchange interaction strength of 0.45 meV at $T=10\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ is inferred.