Enhancement effects on excitonic photoluminescence intensity originating from misaligned crystal blocks and polycrystalline grains in a ZnO wafer
Enhancement effects on excitonic photoluminescence intensity originating from misaligned crystal blocks and polycrystalline grains in a ZnO wafer
复制标题
DOI：
10.1140/epjb/e2012-30502-7
复制
发表时间：
2013-02
期刊：
影响因子：
--
通讯作者：
H. Takeuchi
中科院分区：
文献类型：
--
作者：
H. Takeuchi
我们系统地研究了（0001）取向ZnO晶片中激子光致发光强度与晶体质量之间的关系。我们使用圆偏振测量和反射型X射线形貌测量来可视化整个晶片的晶体质量。反射型X射线形貌图显示出由内部应变引起的颗粒状图案区域。圆偏振图表明内部应变引起局部应力。θ-2θ X射线衍射图表明存在未对准的晶体块和多晶颗粒。我们测量了光致发光谱，发现晶体块和多晶晶粒的存在导致激子光致发光谱强度的增强。这种现象是由于与X射线形貌图中的晶粒状图案相连接的晶粒和畴界抑制了激子的扩散。
We have systematically investigated a relation between excitonic photoluminescence intensity and crystal quality in a (0001)-oriented ZnO wafer. We visualize the crystal quality of a whole wafer using a circular polariscopic measurement and a reflection-type X-ray topograph measurement. The reflection-type X-ray topograph exhibits regions of grain-like patterns that result from internal strains. The circular polariscopic map shows that the internal strains induce local stresses. Theθ-2θX-ray diffraction pattern indicates the presence of misaligned crystal blocks and polycrystalline grains. We have measured photoluminescence spectra and found that the presence of misaligned crystal blocks and polycrystalline grains leads to enhancement of the excitonic photoluminescence intensity. The present phenomenon is attributed to the suppression of exciton diffusion caused by the grain and domain boundaries that connect with the grain-like patterns in the X-ray topograph.