InGaN quantum dot growth in the limits of Stranski–Krastanov and spinodal decomposition

Abstract

Abstract Most commonly used for the self‐assembling of InGaN quantum dots is a Stranski–Krastanov growth scheme. Often neglected is the influence of spinodal decomposition, although it is frequently discussed with quantum well growth. In this publication we will expose the influence of both mechanisms on the formation process of quantum dots. This paper gives an insight in the theoretical background of quantum dot formation and covers the growth by molecular beam epitaxy and metal organic vapor phase epitaxy. Stranski–Krastanov like growth has been verified by the surface evolution beyond the critical thickness as seen by atomic force microscopy on uncapped samples. The overgrowth of such samples led to dissolution of the quantum dots. Indium compositions within the miscibility gap below critical thickness yielded spinodal phase separation in meander like structures These structures are in agreement with the theory from Hilliard and Cahn. Based on spinodal decomposition overgrowth schemes have been developed which showed reliable quantum dot emission. Such layers have been implemented into device structures such as LEDs and laser structures. magnified image