Radiative and nonradiative excitonic transitions in nonpolar (11(2)over-bar-0) and polar (000(1)over-bar) and (0001) ZnO epilayers
Radiative and nonradiative excitonic transitions in nonpolar (11(2)over-bar-0) and polar (000(1)over-bar) and (0001) ZnO epilayers
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DOI：
10.1063/1.1646749
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发表时间：
2004-02-16
影响因子：
4
通讯作者：
Kawasaki, M
中科院分区：
文献类型：
--
作者：
Koida, T;Chichibu, SF;Kawasaki, M
激光分子束外延生长的非极性（11（2）over bar 0）ZnO外延层的偏振反射光谱和光反射光谱显示出各向异性激子共振结构，符合各向异性应变六方材料的偏振选择规则。其激子光致发光（PL）峰的电场分量垂直于[0001]轴偏振。与GaN的情况不同，在293 K下的非辐射PL寿命和S参数（S参数是通过正电子湮没光谱获得的Zn空位相关缺陷密度的量度）的（11（2）over bar 0）ZnO与现有技术的极性（000（1）over bar）和（0001）外延层的那些相当。由于极性外延层表现出明显的激子-极化激元发射，生长方向对缺陷掺入的影响可以忽略不计，这表明外延（11（2）条上的0）ZnO作为在紫外光谱区操作的偏振敏感光电器件的潜在用途。(C)2004年，美国物理学会。
Polarized optical reflectance and photoreflectance spectra of an out-plane nonpolar (11(2) over bar 0) ZnO epilayer grown by laser molecular-beam epitaxy exhibited anisotropic exciton resonance structures according to the polarization selection rules for anisotropically strained hexagonal material. Consistently, the electric field component of its excitonic photoluminescence (PL) peak was polarized perpendicular to the [0001] axis. Different from the case for GaN, nonradiative PL lifetime at 293 K and the S parameter, which is a measure of Zn vacancy-related defect density obtained by positron annihilation spectroscopy, of the (11(2) over bar 0) ZnO were comparable to those of state-of-the-art polar (000(1) over bar) and (0001) epilayers. Since the polar epilayers exhibited pronounced exciton-polariton emissions, the negligible impact of growth direction on the defect incorporation suggests a potential use of epitaxial (11(2) over bar 0) ZnO as polarization-sensitive optoelectronic devices operating in ultraviolet spectral regions. (C) 2004 American Institute of Physics.