Enhanced deep ultraviolet luminescence from AlGaN quantum wells grown in the three-dimensional mode

摘要

We report a significant improvement in the room temperature cathodoluminescence efficiency of AlGaN quantum wells when the three-dimensional growth mode is induced by reduced flux of ammonia. We interpret this observation in terms of formation of quantum dots of AlGaN in Al_(0.45)Ga_(0.55)N wells. Reflection high electron diffraction images and detailed measurements of the cathodoluminescence intensity, linewidth, and wavelength as a function of growth conditions are consistent with the presence of quantum dots.