Spectral diffusion in nitride quantum dots: Emission energy dependent linewidths broadening via giant built-in dipole moments

被引:28
|
作者
Kindel, C. [1 ,2 ]
Callsen, G. [2 ]
Kako, S. [1 ]
Kawano, T. [1 ]
Oishi, H. [1 ]
Hoenig, G. [2 ]
Schliwa, A. [2 ]
Hoffmann, A. [2 ]
Arakawa, Y. [1 ]
机构
[1] Univ Tokyo, Inst Ind Sci, Meguro Ku, Tokyo 1538505, Japan
[2] Tech Univ Berlin, Inst Festkorperphys, D-10623 Berlin, Germany
来源
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS | 2014年 / 8卷 / 05期
关键词
quantum dots; nitrides; quantum-confined Stark effect; dipole moments; spectral diffusion; SINGLE-PHOTON SOURCE; ELECTRONIC-STRUCTURE; TIME;
D O I
10.1002/pssr.201409096
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We present a study about the origin of the huge emission linewidths broadening commonly observed for wurtzite GaN/AlN quantum dots. Our analysis is based on a statistically significant number of quantum dot spectra measured by an automatized mu-photoluminescence mapping system applying image recognition techniques. A clear decrease of the single quantum dot emission linewidths is observed with rising overall exciton emission energy. 8-band k . p based model calculations predict a corresponding decrease of the built-in exciton dipole moments with increasing emission energy in agreement with the measured behavior for the emission linewidths. Based on this proportionality we explain the particular susceptibility of nitride quantum dots to spectral diffusion causing the linewidth broadening via the linear quantum-confined Stark effect. This is the first statistical analysis of emission linewidths that identifies the giant excitonic dipole moments as their origin and estimates the native defect-induced electric field strength to similar to 2 MV/m. Our observation is in contrast to less-polar quantum dot systems as e.g. arsenides that exhibit a naturally lower vulnerability to emission linewidth broadening due to almost negligible exciton dipole moments. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
引用
收藏
页码:408 / 413
页数:6
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