摘要
采用变温及时间分辨光致发光谱研究了MBE设备生长的具有不同盖帽层的InAs量子点样品。发现引入InGaAs盖帽层可以使InAs量子点发光的半高宽减小，且向长波长移动。InGaAs／InAlAs联合盖帽层可以进一步改善InAs量子点发光性能，使得室温发光波长超过1.3μm；在10-300K温度范围内，发光峰值能量及半高宽随温度的变化都较小。随温度升高，InAs量子点的发光寿命首先增大，当温度升高到临界温度Tc后，发光寿命逐渐减小。但覆盖不同盖帽层的InAs量子点样品，其发光寿命具有不同的温度关系，联合盖帽层样品具有较大的Tc及发光寿命。根据应力及栽流子迁移模型对以上实验结果进行了分析。
InAs quantum dots （QDs） with different cap layers were fabricated by molecule beam epitaxy （MBE） system. Temperature-dependent and time-resolved photoluminescence （PL） measurements were employed to study PL properties of InAs QDs. InAs QDs with InGaAs cap layer show an obvious diminution of PL emission full width at half maximum （FWHM） and a red- shift of PL peak. InGaAs and InA1As combination cap layer （CCL） could further improve PL properties of InAs QDs and lead to above 1.3μm emission at room temperature. The smallest FWHM of InAs with CCL is only 24 meV around 240 K and the variations of PL FWHM and peak energies are much smaller than those of the others in the temperature range of 10-300 K. As the temperature increases, PL lifetime rises gradually and reaches a maximum value, the critical temperature Tc and then drops at higher temperature. However, the detailed lifetime- temperature relations for the samples differ from each other. InAs QDs with CCL have the largest Tc and lifetime. A detail analysis is given to explain the experimental results according to the mechanism of stress relaxation and carriers migration.
出处
《半导体光电》
EI
CAS
CSCD
北大核心
2008年第3期349-352,共4页
Semiconductor Optoelectronics
基金
浙江省舟山市科技项目(06110)
浙江海洋学院科研项目(X06LY01)
浙江海洋学院人才引进项目(211050041)
关键词
盖帽层
INAS量子点
时间分辨谱
cap layer
InAs quantum dots
time-resolved photoluminescence
