RELIABLE SYNTHESIS AND MANIPULATION OF SELF-RUNNING GALLIUM DROPLETS ON GALLIUM ARSENIDE (001) IN MBE

Abstract

A procedure for reliable synthesis and the attempts to manipulate self-running Ga droplets on GaAs (001) in a molecular beam epitaxial (MBE) machine have been investigated. The running Ga droplets are studied by atomic force microscopy, differential interference contrast microscopy, and scanning electron microscopy. Their electrical properties are characterized by current-voltage (I-V) measurements. Using the proposed procedure, the formation of self-running Ga droplets has been reliably achieved in MBE despite the lack of real-space and real-time imaging capability. The procedure is based on the observation of in situ reflection high-energy electron diffraction patterns and the registration of an appropriate reference temperature followed by controlled sublimation profiles. The Ga droplet-GaAs interface is probed electrically; preliminary I-V measurements indicate that the interface shows a Schottky behavior. The manipulation of self-running Ga droplets migration using buried defects is proposed and demonstrated in a low-energy electron microscope. The Ga droplets are found to run and take sharp turns upon meeting with defects, possibly from Ga-spitting. Such results provide new insights of the running droplets dynamics and may open up opportunities to steer the droplets motion.