Temperature Dependence of Emission Properties of Self-Assembled InGaN Quantum Dots
ZHAO Wan-Ru1, WENG Guo-En2, LIANG Ming-Ming2, LI Zeng-Cheng3, LIU Jian-Ping3, ZHANG Jiang-Yong1, ZHANG Bao-Ping1**
1Optoelectronics Engineering Research Center, Department of Electronic Engineering, Xiamen University, Xiamen 361005 2Department of Physics, Xiamen University, Xiamen 361005 3Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123
Abstract：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 (15–300 K), 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 (MQWs). 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 MQWs, 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 MQWs. By analyzing the integrated PL intensity, the larger confinement energy of localized states in the QDs is estimated to be 105.9 meV, 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.
2014, Vol. 31 
