摘要
利用金属有机物化学气相沉积技术在蓝宝石衬底(0001)面生长了InGaN/GaN多量子阱结构,并测量了其荧光(PL)光谱的峰位能量和发光效率对温度和注入载流子密度的依赖性.结果显示,该样品PL的峰位能量对温度的依赖性是"S形"的(降低-增加-降低),并且最大发光效率出现在50 K左右.前者反映了InGaN阱层中势能的非均一性和载流子复合的局域特征,后者则表明了将极低温度下的内量子效率设定为100%的传统界定方法应当被修正.进一步的研究结果显示,发光效率不仅是温度的函数,同时也是注入载流子密度的函数.为此我们对传统的基于PL光谱测量来确定某结构(或器件)内量子效率的方法进行了修正:在不同温度下测量发光效率对注入载流子密度的依赖性,并将发光效率的最大值设为内量子效率是100%,这样,其他温度点和注入载流子密度点所对应的内量子效率也就随之确定.
The InGaN/GaN multiple quantum wells are grown on a （0001）-oriented sapphire by using metalorganic chemical vapor deposition. Dependences of the photoluminescence （PL） peak energy and PL efficiency on injected carrier density and temperature are studied. The results show that the temperature-dependent behavior of the peak energy is in the manner of decrease-increase-decrease （S-shaped）, and the maximum of the PL efficiency is observed at about 50 K. The former is attributed to the potential inhomogeneity and local characteristics of the carrier recombination in the InGaN matrix. The latter indicates that the traditional method that the internal quantum efficiency （IQE） is considered to be 100%at low temperature, should be corrected. Furthermore, it is found that the IQE depends on not only temperature but also injected carrier density. Based on the above discussion, an improved method of setting the IQE, i.e., measuring the dependence of PL efficiency is proposed.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2014年第12期343-349,共7页
Acta Physica Sinica
基金
高等学校博士学科点专项科研基金(批准号:20120131110006)
山东省科技发展计划(批准号:2013GGX10221)
国家自然科学基金(批准号:61306113)资助的课题~~
作者简介
通讯作者．E-mail：jiziwu@sdu．edu．cn
