Advances in growth and optical properties of GaN-based quantum dots

GaN-based quantum-dot systems have received great attention and revealed unique zero-dimensional features of localized excitons in those quantum dots. In this article, we review recent advances in growth and optical properties of the GaN-based quantum dots focusing on hexagonal GaN quantum dots, which are unique in terms of the existence of a strong built-in electric field due to a spontaneous polarization and a piezoelectric field. In addition, we also discuss their potential applications to advanced light-emitting devices, such as lasers and single-photon sources. Especially, the application to quantum information devices including single-photon sources with a GaN quantum dot is a promising direction because the GaN quantum dots have the potential for operation at higher temperatures. For such applications to quantum information technology, fine tuning and controlling of the electronic states are indispensable, which are generally performed via the quantum-confined Stark effect. We have demonstrated the large tunability of the energy level in a GaN quantum dot by externally applying an electric field. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.