Deep Ultraviolet Luminescence Due to Extreme Confinement in Monolayer GaN/Al(Ga)N Nanowire and Planar Heterostructures
Deep Ultraviolet Luminescence Due to Extreme Confinement in Monolayer GaN/Al(Ga)N Nanowire and Planar Heterostructures
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DOI：
10.1021/acs.nanolett.9b02847
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发表时间：
2019-11-01
期刊：
影响因子：
10.8
通讯作者：
Bhattacharya, Pallab
中科院分区：
文献类型：
--
作者：
Aiello, Anthony;Wu, Yuanpeng;Bhattacharya, Pallab
我们目前的实验结果证实极端的量子限制在GaN/AlxGa 1-xN（x = 0.65和1.0）纳米线和平面异质结构，其中GaN层的厚度是一个单层的顺序。从温度和激发依赖性和时间分辨的光致发光测量的结果。在GaN/AlN纳米线异质结构阵列样品中，在300 K处测量的发射峰类似于5.18-5.28 eV。这与计算的光学带隙5.23 eV和低于计算的电子带隙5.44 eV的160-260 meV非常一致，表明观察到的发射本质上是激子的，激子结合能类似于160-260 meV。类似地，在单层GaN/Al 0.65Ga 0.35N平面异质结构中，在300 K下测量的发射峰为4.785 eV，并且与计算的光学带隙4.68 eV和低于计算的电子带隙4.88 eV的95 meV良好地一致。估计的激子结合能为95毫电子伏，并与我们的理论计算密切一致。依赖于激发和时间分辨的光致发光数据支持激子跃迁的存在。我们的研究结果表明，深紫外激子光源和微腔器件可以实现与异质结构纳入单层厚的GaN。
We present experimental results confirming extreme quantum confinement in GaN/AlxGa1-xN (x = 0.65 and 1.0) nanowire and planar heterostructures, where the GaN layer thickness is of the order of a monolayer. The results were obtained from temperature- and excitation-dependent and time resolved photoluminescence measurements. In the GaN/AlN nanowire heterostructure array sample, the measured emission peak at 300 K is similar to 5.18-5.28 eV. This is in excellent agreement with the calculated optical gap of 5.23 eV and 160-260 meV below the calculated electronic gap of 5.44 eV, suggesting that the observed emission is excitonic in nature with an exciton binding energy of similar to 160-260 meV. Similarly, in the monolayer GaN/Al0.65Ga0.35N planar heterostructure, the measured emission peak at 300 K is 4.785 eV and in good agreement with the calculated optical gap of 4.68 eV and 95 meV below the calculated electronic gap of 4.88 eV. The estimated exciton binding energy is 95 meV and in close agreement with our theoretical calculations. Excitation-dependent and time-resolved photoluminescence data support the presence of excitonic transitions. Our results indicate that deep-ultraviolet excitonic light sources and microcavity devices can be realized with heterostructures incorporating monolayer-thick GaN.