Temperature and excitation dependence of stimulated emission and spontaneous emission in InGaN epilayer

• 来源期刊: 中国物理B（英文版）
• 关键词: InGaN stimulated emission spontaneous emission carrier transfer
• 年，卷（期）: 2019,（5）
• 页码范围: 386-392
• 页数: 7页
• 语种: 英文
• DOI: 10.1088/1674-1056/28/5/057802

摘要

Temperature and excitation dependent photoluminescence (PL) of InGaN epilayer grown on c-plane GaN/sapphire template by molecular beam epitaxy (MBE) has been systematically investigated. The emission spectra of the sample consisted of strong multiple peaks associated with one stimulated emission (SE) located at 430 nm and two spontaneous emissions (SPE) centered at about 450 nm and 480 nm, indicating the co-existence of shallow and deep localized states. The peak energy of SE exhibiting weak s-shaped variation with increasing temperature revealed the localization effect of excitons. Moreover, an abnormal increase of the SPE intensity with increasing temperature was also observed, which indi-cated that the carrier transfer between the shallow and deeper localized states exists. Temperature dependent time-resolved PL (TRPL) demonstrated the carrier transfer processes among the localized states. In addition, a slow thermalization of hot carriers was observed in InGaN film by using TRPL and transient differential refl ectivity, which is attributed to the phonon bottleneck effect induced by indium aggregation.