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Exciton localization behaviour in different well width undoped GaN/Al0.07Ga0.93N nanostructures |
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| Authors: | M Sabooni M Esmaeili H Haratizadeh B Monemar P Paskov S Kamiyama M Iwaya H Amano I Akasaki |
| Institution: | 1. Department of Physics, Islamic Azad University, Shahrood Branch, Shahrood, Iran 2. Departments of Physics, Shahrood University of Technology, Shahrood, Iran 3. Departments of Physics and Measurements Technology, Link?ping University, S-581 83, Link?ping, Sweden 4. Department of Materials Science and Engineering and Hi-Tech Research Center, Meijo University, 1-501 Shiogamaguchi, Tempaku-ku, Nagoya, 468, Japan |
| Abstract: | We report results from optical spectroscopy such as photoluminescence (PL) and time resolved photo-luminescence (TRPL) techniques from different well width MOCVD grown GaN/Al0.07Ga0.93N MQW samples. There is evidence of localization at low temperature in all samples. The decay time of all samples becomes non-exponential when the detection energy is increased with respect to the peak of the emission. Localization of carriers (excitons) is demonstrated by the “S-shape” dependences of the PL peak energies on the temperature. The time-resolved PL spectra of the 3-nm well multi quantum wells reveal that the spectral peak position shifts toward lower energies as the decay time increases and becomes red-shifted at longer decay times. There is a gradient in the PL decay time across the emission peak profile, so that the PL process at low temperatures is a free electron-localized hole transition. |
| Keywords: | photoluminescence time-resolved photoluminescence quantum well exciton localization GaN/AlGaN |
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