Optical polarisation anisotropy in a -plane GaN/AlGaN multiple quantum well structures
Optical polarisation anisotropy in a -plane GaN/AlGaN multiple quantum well structures
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a 平面 GaN/AlGaN 多量子阱结构中的光学偏振各向异性
DOI：
10.1002/pssc.200880796
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Badcock T
中科院分区：
文献类型：
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作者：
Badcock T
本文报道了一系列不同阱宽的a面GaN/AlGaN多量子阱结构的光学性质。每种结构的低温光致发光光谱的特征在于两个不同的发射带，这两个发射带都随着阱厚度的减小而向更高的能量移动。较低能量发射带的起源归因于被基面堆垛层错包围的量子威尔斯阱区域中捕获的载流子的复合。较高的能量特征被分配到本地化的激子复合在阱宽波动。我们已经使用光致发光激发光谱来揭示量子威尔斯的能带结构的细节。用非偏振光激发导致观察到与n = 1和n = 2电子子带相关的激子跃迁。对于线性极化（E c和E c）激发，与非偏振光观察到的过渡被证明是由重叠的过渡，涉及重和轻空穴一样的价电子带。他们所观察到的偏振各向异性归因于各向异性双轴压应变的GaN膜。以及激子跃迁，我们也能够解决定义良好的连续边缘的一些激发光谱。这使我们能够估计的激子结合能的n = 1的重和轻的空穴态的量子威尔斯的不同宽度。发现值在38至76 ±5 meV的范围内。（© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA，魏因海姆）
In this paper we report on the optical properties of a series ofa‐plane GaN/AlGaN multiple quantum well structures of varying well width. The low temperature photoluminescence spectrum of each structure is characterised by two distinct emission bands, both of which shift to higher energy with decreasing well thickness. The origin of the lower energy emission band is attributed to the recombination of carriers trapped in regions of the quantum wells intersected by basal plane stacking faults. The higher energy feature is assigned to localised exciton recombination at well width fluctuations. We have used photoluminescence excitation spectroscopy to reveal details of the bandstructure of the quantum wells. Excitation with unpolarised light resulted in the observation of exciton transitions associated with the n = 1 and n = 2 electron sub‐bands. For linearly polarised (E⊥c and E‖c) excitation, both the transitions observed with unpolarised light were shown to consist of overlapping transitions involving heavy and light hole like valence subbands. Their observed polarisation anisotropy was attributed to anisotropic biaxial compressive strain in the GaN film. As well as the exciton transitions we were also able to resolve well defined continuum edges in some of the excitation spectra. This enabled us to estimate the exciton binding energy of the n = 1 heavy and light hole states for quantum wells of differing width. Values were found to lie in the range of 38 to 76 ±5 meV. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)