Study of the chemical and morphological evolution of InSb(001) surface under low energy ion bombardment

Abstract

InSb(001) surfaces were subjected to 4keV Ar+ bombardment at oblique angles of incidence with ion fluences in the range of 9.0×1013–6.2×1017ions/cm2. The evolution of bombardment induced surface structures and their chemical composition were studied with Atomic Force Microscopy (AFM) and Kelvin Probe Force Microscopy (KPFM) in UHV, and “ex situ” with Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray spectroscopy (EDX). Various morphological features, such as small dots, wires and for very high ion fluence ripple-like structures were observed. It was found that both the initial surface crystallographic structure and the ion beam direction influence the developing anisotropic nanostructures on the irradiated surface. It was also found that the time evolution of the nanostructured surface in terms of surface roughness σ, follows a power law σ∼tβ. The surface nanostructures (dots and wires), at every stage of their development, are found to have different work functions in comparison to the surrounding InSb substrate. The results indicate that the nanostructures developed on the irradiated InSb surfaces consist of indium.