Quantum-confined stark effect and localization of charge carriers in Al0.3Ga0.7N/Al0.4Ga0.6N quantum wells with different morphologies
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- Shevchenko, E.A., Jmerik, V.N., Mizerov, A.M. et al. Semiconductors (2012) 46: 998. doi:10.1134/S1063782612080192
The electric fields in Al0.3Ga0.7N/Al0.4Ga0.6N quantum wells are estimated. The quantum wells are grown by plasma-assisted molecular-beam epitaxy with plasma activation of nitrogen. The three-dimensional and planar modes of buffer layer growth are used. The transition to the three-dimensional mode of growth yields a substantial increase in the photoluminescence intensity of the quantum wells and a shift of the photoluminescence line to shorter wavelengths. These effects are attributed to the fact that, because of the extra three-dimensional localization of charge carriers in the quantum-well layer, the quantum-confined Stark effect relaxes. The effect of localization is supposedly due to spontaneous composition fluctuations formed in the AlGaN alloy and enhanced by the three-dimensional growth.