Optical And Vibrational Properties Of Self-Assembled Gan Quantum Dots

This chapter describes quantum dots (QDs) based on group III nitrides (III-N). They are expected to be the active medium of new optoelectronic devices operating at high powers and high temperatures. Besides the well-known advantages of their bulk and quantum well (QW) counterparts, III-N QDs provide strong confinement of carriers in nearly perfect zero-dimensional boxes. Quantum effects provide new degrees of freedom for the design of advanced devices. The chapter reviews the systems of dots that appear spontaneously during epitaxial growth without the need of artificial post-processing and designate them as self-assembled or self-organized QDs regardless of the mechanism responsible for their appearance. It provides a brief overview of the most relevant growth techniques employed for the spontaneous or self-assembled growth of GaN QDs. Special attention will be paid to epitaxial growth categorized into two different modes: Volmer–Weber (VW) mode corresponding to three-dimensional (3D) island growth and Stranski–Krastanov (SK) mode, where the deposition of a strained two-dimensional (2D) wetting layer is followed by elastic relaxation through 3D islanding.