Optical and microstructural properties of semi‐polar (11‐22) InGaN/GaN quantum well structures
Optical and microstructural properties of semi‐polar (11‐22) InGaN/GaN quantum well structures
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半极性（11-22）InGaN/GaN量子阱结构的光学和微观结构特性
DOI：
10.1002/pssc.200880840
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
C. Humphreys
中科院分区：
文献类型：
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作者：
N. Hylton;P. Dawson;C. Johnston;M. Kappers;J. Hollander;C. McAleese;C. Humphreys
本文报道了一系列半极性（11-22）InGaN/GaN多量子阱结构与一系列极性（0001）对照样品的光学性质的比较。在半极性结构中，我们观察到量子阱发射的蓝移，辐射复合率的增加和量子阱激发光谱的锐化;所有这些变化与相对于对照样品的电场强度的大小的降低是相容的。然而，电场强度的降低并不转化为室温下光致发光内量子效率的提高。我们将这种失败归因于非辐射复合中心密度的增加，这是由（11-22）样品中较大的位错密度引起的。使用TEM和STEM-HAADF测量，我们还观察到（11-22）样品中的总阱宽波动，这导致光致发光光谱的加宽。（© 2009 WILEY-VCH Verlag GmbH & Co. KGaA，魏因海姆）
In this paper we report on a comparison of the optical properties of a series of semi-polar (11-22) InGaN/GaN multiple quantum well structures with those of a series of polar (0001) control samples. In the semi-polar structures we observe blue-shifts of the quantum well emission, increases of the radiative recombination rates and sharpening of the quantum well excitation spectra; all these changes are compatible with a decrease in the magnitude of the electric field strength with respect to the control samples. However the reduction in the electric field strength does not translate into an improvement in the photoluminescence internal quantum efficiency at room temperature. This failure we attribute to an increased density of non-radiative recombination centres, arising from the larger dislocation density in the (11-22) samples. Using TEM and STEM-HAADF measurements we have also observed gross well width fluctuations in the (11-22) samples which result in broadening of the photoluminescence spectra. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)