Emission mechanisms in Al-rich AlGaN/AlN quantum wells assessed by excitation power dependent photoluminescence spectroscopy
Emission mechanisms in Al-rich AlGaN/AlN quantum wells assessed by excitation power dependent photoluminescence spectroscopy
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DOI：
10.1063/1.4908282
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发表时间：
2015-02-21
影响因子：
3.2
通讯作者：
Kawakami, Yoichi
中科院分区：
文献类型：
--
作者：
Iwata, Yoshiya;Banal, Ryan G.;Kawakami, Yoichi
通过激发功率相关的时间积分（TI）和时间分辨（TR）光致发光（PL）测量，评估了富al AlGaN/AlN量子阱的光学性质。两个激发源，一个光学参量振荡器和Ti：蓝宝石激光器的四次谐波，实现了10（12）和10(21)cm（-3）之间的宽范围的激发载流子密度。随着激发功率的增加，发射机制由激子转变为电子空穴等离子体。因此，PL衰减时间大大缩短，并且集成PL强度按以下顺序增加：线性，超线性，再次线性和亚线性。考虑非辐射复合过程的饱和效应的速率方程很好地解释了观察到的结果。使用TIPL和TRPL测量可以可靠地提取非辐射复合中心的密度、内部量子效率和辐射复合系数。(C) 2015 AIP出版有限责任公司
The optical properties of Al-rich AlGaN/AlN quantum wells are assessed by excitation-power-dependent time-integrated (TI) and time-resolved (TR) photoluminescence (PL) measurements. Two excitation sources, an optical parametric oscillator and the 4th harmonics of a Ti:sapphire laser, realize a wide range of excited carrier densities between 10(12) and 10(21) cm(-3). The emission mechanisms change from an exciton to an electron-hole plasma as the excitation power increases. Accordingly, the PL decay time is drastically reduced, and the integrated PL intensities increase in the following order: linearly, super-linearly, linearly again, and sub-linearly. The observed results are well accounted for by rate equations that consider the saturation effect of non-radiative recombination processes. Using both TIPL and TRPL measurements allows the density of non-radiative recombination centers, the internal quantum efficiency, and the radiative recombination coefficient to be reliably extracted. (C) 2015 AIP Publishing LLC.