We have investigated the optical and phototransport properties of GaN/AlGaN quantum wells by photoluminescence and photovoltage spectroscopy. We show that the internal piezoelectric and spontaneous polarization fields cause a strong red-shift of the ground level energy of the quantum wells. Furthermore, identical quantum wells grown on different buffer layers (GaN or AlGaN) exhibit different emission energies, but similar well-width dependence of the n = 1 state, due to the different distribution of strain between well and barrier. The built-in field also causes a strong reduction of the exciton oscillator strength, which is not observable in photovoltage spectra. A long-living (thousands of seconds) charge storage effect is observed in the phototransport spectra due to the presence of point defects, presumably associated to Ga vacancies.
Lomascolo, M., Traetta, G., Passaseo, A., Longo, M., Cannoletta, D., Cingolani, R., et al. (2000). Optical and transport properties of GaN/Al0.15Ga0.85N quantum wells. PHYSICA STATUS SOLIDI. A, APPLIED RESEARCH, 178(1), 73-78 [10.1002/1521-396X(200003)178:1<73::AID-PSSA73>3.0.CO;2-A].
Optical and transport properties of GaN/Al0.15Ga0.85N quantum wells
Longo, M.;Di Carlo, A.;
2000-01-01
Abstract
We have investigated the optical and phototransport properties of GaN/AlGaN quantum wells by photoluminescence and photovoltage spectroscopy. We show that the internal piezoelectric and spontaneous polarization fields cause a strong red-shift of the ground level energy of the quantum wells. Furthermore, identical quantum wells grown on different buffer layers (GaN or AlGaN) exhibit different emission energies, but similar well-width dependence of the n = 1 state, due to the different distribution of strain between well and barrier. The built-in field also causes a strong reduction of the exciton oscillator strength, which is not observable in photovoltage spectra. A long-living (thousands of seconds) charge storage effect is observed in the phototransport spectra due to the presence of point defects, presumably associated to Ga vacancies.File | Dimensione | Formato | |
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Optical and Transport Properties of GaN Al0 15Ga0 85N Quantum Wells.pdf
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