Photoluminescence studies of cubic GaN epilayers
Photoluminescence studies of cubic GaN epilayers
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DOI：
10.1002/pssb.201600733
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发表时间：
2017-08-01
影响因子：
1.6
通讯作者：
Dawson, P.
中科院分区：
文献类型：
--
作者：
Church, S. A.;Hammersley, S.;Dawson, P.
研究了通过 MOCVD 在 3C-SiC/Si (001) 衬底上生长的立方 GaN 薄膜的发光特性。光谱显示与供体结合激子重组和供体受体对重组相关的发光峰。与文献报道的值相比，(DX)-X-0 发射的峰值能量降低，表明拉伸应变减小的带隙约为 3.27eV，这与光致发光激发光谱中的吸收边一致。六方材料的存在引入了 3.40eV 的宽发射带，半高宽为 190meV，能量延伸至高达 3.60eV。这种发射的强度与激发功率成线性比例，其峰值能量和宽度保持不变。该能带与低于 3.70eV 的吸收边相关，因此不是由纯相立方或六方 GaN 的吸收引起的。随着发射能量的增加，在该波段测量的光致发光寿命从 0.40 纳秒减少到 0.20 纳秒。所有这些观察结果都可以通过考虑立方 GaN 内堆垛层错附近的 II 型能带排列来解释。 (C) 2017 WILEY-VCH Verlag GmbH & Co. KGaA，魏因海姆
The luminescence properties of cubic GaN films grown upon 3C-SiC/Si (001) substrates by MOCVD were investigated. The spectra show luminescence peaks which are associated with donor bound exciton recombination and donor acceptor pair recombination. A reduced peak energy for the (DX)-X-0 emission compared with values reported in the literature suggests a tensile-strain-reduced bandgap of approximately 3.27eV, which is consistent with the absorption edge in photoluminescence-excitation spectroscopy. The presence of hexagonal material introduces a broad emission band at 3.40eV with a FWHM of 190meV, extending to energies up to 3.60eV. The intensity of this emission scales linearly with excitation power, its peak energy and width remaining unchanged. This band is associated with an absorption edge below 3.70eV and therefore is not caused by absorption into phase-pure cubic or hexagonal GaN. The photoluminescence lifetimes measured across this band reduce from 0.40 to 0.20ns with increasing emission energy. All these observations can be explained by considering a type-II-band alignment adjacent to stacking faults within the cubic GaN. (C) 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim