Exciton spectra of an AlN epitaxial film on (0001) sapphire substrate grown by low-pressure metalorganic vapor phase epitaxy
Exciton spectra of an AlN epitaxial film on (0001) sapphire substrate grown by low-pressure metalorganic vapor phase epitaxy
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DOI：
10.1063/1.1493666
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发表时间：
2002-07-22
影响因子：
4
通讯作者：
Tanaka, M
中科院分区：
文献类型：
--
作者：
Onuma, T;Chichibu, SF;Tanaka, M
采用光学反射（OR）和阴极发光测量方法，测量了低压金属有机物气相外延（0001）蓝宝石衬底上AlN外延层的激子共振能量随温度的变化。OR光谱在多次内反射条纹正上方的光子能量处表现出明显的反射率异常，并且考虑A（Gamma（7v）（u）->Gamma（7 c））和BC（Gamma（9v），Gamma（7v）（l）->Gamma（7 c））激子跃迁来拟合谱线形状。拟合给出它们在0 K下的值为6.211和6.266 eV，给出约55 meV的晶场分裂（Delta（cr））。AlN薄膜即使在300 K下也表现出激子发射，这是由于激子的小玻尔半径和大的纵向光学声子能量。爱因斯坦特征温度θ（E）估计为580 K。(C)2002年美国物理学会。
Exciton resonance energies in an AlN epilayer on (0001) sapphire substrate grown by low-pressure metalorganic vapor phase epitaxy were determined as a function of temperature by means of optical reflectance (OR) and cathodoluminescence measurements. The OR spectra exhibited distinct reflectance anomalies at the photon energies just above the multiple internal reflection fringes, and the spectral line shape was fitted considering A (Gamma(7v)(u)-->Gamma(7c)) and BC (Gamma(9v),Gamma(7v)(l)-->Gamma(7c)) exciton transitions. The fitting gave the values of them at 0 K to be 6.211 and 6.266 eV, giving the crystal- field splitting (Delta(cr)) of approximately 55 meV. The AlN film exhibited an excitonic emission even at 300 K, which is due to the small Bohr radius of excitons and large longitudinal optical phonon energies. The Einstein characteristic temperature Theta(E) was estimated to be 580 K. (C) 2002 American Institute of Physics.