NM02 – Impact of random alloy fluctuations on the electronic and optical properties of c-plane AlxGa1−xN/AlN quantum wells

We present a theoretical study of the electronic and optical properties of c-plane Al_xGa_1−xN/AlN quantum wells emitting in the ultraviolet-A (UV-A) to UV-C spectral range. Special attention is paid to the impact of alloy fluctuations on the results. We find that random alloy fluctuations in (Al,Ga)N are already sufficient to cause strong carrier localization effects. Moreover, our results suggest that the degree of optical polarization is impacted by alloy induced carrier localization effects. More specifically, in comparison to a virtual crystal approximation, which neglects effects of alloy disorder, the switching from transverse electric to transverse magnetic polarization occurs
at higher Al contents. This feature is important for the light extraction efficiencies of (Al,Ga)N-based light emitters operating in the deep UV spectral range.