Photoluminescence Study of Rapid Thermal Annealed GaAs/AlGaAs Quantum Dots Formed by Low Energy Ion Sputtering
Abstract:Rapid thermal annealing of GaAs/AlGaAs quantum dots (QDs) formed by ion sputtering and molecular beam epitaxy (MBE) growth is investigated and characterized. While improvement in the optical properties is observed for all annealed QD samples, both photoluminescence (PL) intensity and spectral line width are found to be optimized at 600 °C annealing temperature and 30 secs annealing time. Two activation energies, E 1 = 6.2±0.9 meV and E 2 = 37.5±2.5 meV, are extracted from the temperature dependent PL of the optimized sample. Since E 2, which is responsible for the PL quenching at higher temperature, is comparable to that of the as-grown sample, the GaAs/AlGaAs QDs formed by the reported technique undergoes minimum energy band structure modification and therefore negligible inter-diffusion. This is consistent with the QD peak's resistance to blue-shift after annealing. The result suggests that the reported fabrication technique is significant for applications that aim to improve the radiative emission efficiency of GaAs/AlGaAs QDs by RTA without introducing large undesirable blueshift.
Document Type: Research Article
Publication date: 2010-12-01
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