Temperature Dependence of the Optical Properties of High-density GaAs Quantum Dots
- Resource Type
- Article
- Authors
- Ryan P. Smith; 김종수; 이상준; 노삼규; 김진수; 임재영; 송진동
- Source
- Journal of the Korean Physical Society, 60(9), pp.1428-1432 May, 2012
- Subject
- 물리학
- Language
- English
- ISSN
- 1976-8524
0374-4884
We investigate the effect of the quantum dot (QD) density on the thermal escape and the retrapping processes of carriers for unstrained GaAs/AlGaAs QDs through temperature-dependent photoluminescence measurements. We fabricated high-density GaAs QDs (8.4 ?1010/cm2, dot-dot distance ∼34 nm) on an Al0.3Ga0.7As/GaAs (111)A surface by using droplet epitaxy. The average lateral size and height of the GaAs QDs are 24 and 6 nm, respectively. Temperature-dependent photoluminescence (PL) studies show that high-density GaAs QDs undergo a sigmoidal-shape energy shift. The sigmoidal dependence of the PL peak energy can be explained by thermal escaping of carriers followed by re-trapping by QDs. Our analysis indicates that the re-trapping probability of thermally-escaped carriers increases with decreasing dot-to-dot distance (corresponding to an increase in the QD density).