title: Influence of excitation power and temperature on photoluminescence in InGaN/GaN multiple quantum wells.
abstract: Excitation power and temperature dependences of the photoluminescence (PL) spectra are studied in InGaN/GaN multiple quantum wells (MQWs). The excitation power dependences of the PL peak energy and linewidth indicate that the emission process of the MQWs is dominated first by the Coulomb screening effect and then by the localized states filling at low temperature, and that the nonradiative centers are thermally activated in low excitation range at room temperature. The anomalous temperature dependences of the peak energy and linewidth are well explained by the localized carrier hopping and thermalization process, and by the exponentially increased density of states with energy in the band tail. Moreover, it is also found that internal quantum efficiency is related to the mechanism conversion from nonradiative to radiative mechanism, and up to the carriers escaping from localized states.
authors.affiliation: School of Physics, Shandong University, Jinan 250100, China.
authors.forename: Huining
authors.initials: H
authors.lastname: Wang
authors.forename: Ziwu
authors.initials: Z
authors.lastname: Ji
authors.forename: Shuang
authors.initials: S
authors.lastname: Qu
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
authors.forename: Yongzhi
authors.initials: Y
authors.lastname: Jiang
authors.forename: Baoli
authors.initials: B
authors.lastname: Liu
authors.forename: Xiangang
authors.initials: X
authors.lastname: Xu
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Mino