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Emission properties of self-assembled green-emitting InGaN quantum dots (QDs) grown on sapphire substrates by using metal organic chemical vapor deposition are studied by temperature-dependent photoluminescence (PL) measurements. As temperature increases (15-300K), the PL peak energy shows an anomalous V-shaped (redshift blueshift) variation instead of an S-shaped (redshift-blueshift-redshift) variation, as observed typically in green-emitting InGaN/GaN multi-quantum wells (MOWs). The PL full width at half maximum (FWHM) also shows a V-shaped (decrease-increase) variation. The temperature dependence of the PL peak energy and FWHM of QDs are well explained by a model similar to MOWs, in which carriers transferring in localized states play an important role, while the confinement energy of localized states in the QDs is significantly larger than that in MOWs. By analyzing the integrated PL intensity, the larger confinement energy of localized states in the QDs is estimated to be 105.9meV, which is well explained by taking into account the band-gap shrinkage and carrier thermalization with temperature. It is also found that the nonradiative combination centers in QD samples are much less than those in QW samples with the same In content. 相似文献
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针对嫦娥三号探月卫星运行过程,主要探究嫦娥三号软着陆过程中着陆目标区域的选取。根据不同地域所拍摄照片像素点数值大小不同的特性,通过构造、计算平坦系数并建立合适的空间直角坐标系,从而找出相对平坦区域,根据路径最小原则,选取嫦娥三号的最佳着陆地点,并给出相应的轨迹方程。 相似文献
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