Ordered Quantum Dot Formation by Ion Sputtering

Abstract

Ion sputtering with low energy ions at normal angle of incidence represents an alternative method for the self-organized formation of semiconductor quantum dots. Dot patterns are formed spontaneously on GaSb and InSb surfaces during sputtering and exhibit a uniform size distribution and a long-range hexagonal ordering. The diameter of the fabricated dots ranges from 15–80 nm with an aspect ratio of nearly unity and with dot densities of 3 × 1011 to 1 × 1010 cm—2. The size and density of the dots can be controlled separately by sputtering time and ion energy, respectively. GaSb quantum dots are prepared by this method through sputtering of GaSb layers in a multilayer sample down to the interface. Numerical integration of the Kuramoto-Sivashinsky equation which describes in a continuum model the dot formation are compared to the experimental findings.