Size and density control of In droplets at near room temperatures

Abstract

We report on the ability to control the size and density of In droplets on GaAs(100) substrates atnear room temperatures using solid source molecular beam epitaxy. We specifically demonstratethe height, diameter and density control of In droplets as functions of substrate temperature(Tsub) and monolayer (ML) coverage. For a range of density (∼109–1010 cm−2), the growth window is revealed to be between 20 and70 °C. For a fixed ML coverage, the size and density of droplets can be controlled by controlling theTsub. For afixed Tsub, bycontrolling the ML coverage, droplet size and density can be controlled. Even at near room temperatures(20–70 °C), In atoms are extremely sensitive to surface diffusion and this enables the control of thesize and density of droplets. This study provides an aid to understanding theformation of In droplets at near room temperatures and can find applications inthe formation of quantum structures and/or nanostructures based on dropletepitaxy.