Asymmetrical In{sub 0.1}Ga{sub 0.9}As/Al{sub 0.3}Ga{sub 0.7}As quantum rings and their optical properties
- Semiconductor Device Research Laboratory (Nanotech Center of Excellence) Department of Electrical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok (Thailand)
In{sub 0.1}Ga{sub 0.9}As/Al{sub 0.3}Ga{sub 0.7}As quantum rings were fabricated by droplet epitaxy technique using molecular beam epitaxy (MBE). 7.5 ML In{sub 0.1}Ga{sub 0.9}As droplets are deposited on Al{sub 0.3}Ga{sub 0.7}As epitaxial layer at 350°C and 250°C. After that, they were crystallized under As{sub 4} pressure of 8×10{sup −6} torr at 250°C. The surface morphology of quantum rings is studied by atomic force microscopy. It is found that quantum rings are not symmetrical due to anisotropic behavior of In and Ga atom migration during crystallization process. The quantum ring density of the sample deposition at 350°C and 250°C are 1×10{sup 9} cm{sup −2} and 2.6×10{sup 9} cm{sup −2}, respectively. Consequently, the asymmetric quantum rings with deposition at 350°C give two photoluminescence (PL) peaks at 1.27 and 1.38 eV at 20K. However, the PL peak of quantum rings with deposition at 350°C is merged with GaAs peak due to the poor size distribution.
- OSTI ID:
- 22261932
- Journal Information:
- AIP Conference Proceedings, Vol. 1566, Issue 1; Conference: ICPS 2012: 31. international conference on the physics of semiconductors, Zurich (Switzerland), 29 Jul - 3 Aug 2012; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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