Effects of Rapid Thermal Annealing on the Optical Properties of GaAs Quantum Dots Grown by Using the Droplet Epitaxy Method

Title
Effects of Rapid Thermal Annealing on the Optical Properties of GaAs Quantum Dots Grown by Using the Droplet Epitaxy Method
Author(s)
김종수Hyun Young Choi[Hyun Young Choi]Min Young Cho[Min Young Cho]Min Su Kim[Min Su Kim]Jae-Young Leem[Jae-Young Leem]Dong-Yul Lee[Dong-Yul Lee]Jin Soo Kim[Jin Soo Kim]
Keywords
MOLECULAR-BEAM EPITAXY; GAAS/ALGAAS QUANTUM; PHOTOLUMINESCENCE SPECTRA; TEMPERATURE; DEPENDENCE; LAYER
Issue Date
201105
Publisher
KOREAN PHYSICAL SOC
Citation
JOURNAL OF THE KOREAN PHYSICAL SOCIETY, v.58, no.5, pp.1324 - 1329
Abstract
GaAs/Al(0.3)Ga(0.7)As quantum dots (QDs) were fabricated by using the droplet epitaxy (DE) method. A one-step rapid thermal annealing (RTA) treatment on all of the QD samples was performed at 740 degrees C. Temperature and excitation power density dependences of photoluminescence (PL) were determined to investigate optical properties. When the temperature is increased from 15 to 200 K, the PL peak energy is red-shifted from 1.648 to 1.590 eV while the full width at. half maximum (FWHM) is increased. Non-radiative recombination is found to be clue to the PL quenching mechanisms at high temperatures. The activation energy (E(a)) is approximately 32 meV. When the integrated PL intensity (I(PL)) is plotted against the excitation power density on log-log scale at different temperatures, we find that the superlinearity becomes stronger as the temperature increases. To investigate the effect of annealing temperature on the optical properties of the QDs. we carried out the two-step RTA treatment at various temperatures from 800 to 1000 degrees C. As the temperature increases, the PL peak position is blue-shifted clue to the change in the composition and the size distribution, and the highest PL intensity is observed for the sample annealed at 900 degrees C. The I(PL) versus the excitation power density shows a slope that changes with changing temperature in the two-step RTA.
URI
http://hdl.handle.net/YU.REPOSITORY/25221http://dx.doi.org/10.3938/jkps.58.1324
ISSN
0374-4884
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이과대학 > 물리학과 > Articles
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