Near-field evidence of local polarized emission centers in InGaN/GaN materials

Abstract

We study the optical polarization properties of confined structures in InGaN/GaN single quantum well devices. Using a near-field optical setup we investigated the photoluminescence maps with a polarization-modulation method. If the optical emissions have a preferred polarization orientation, our apparatus yields a signal that is proportional to the degree of polarization. We could demonstrate that within the quantum well there are localized submicrometer centers that emit strongly oriented light. This points toward the existence of quantum-dot like confined asymmetric domains hidden within the quantum well.