Studies of self-organized Nanostructures on InP(111) surfaces after low energy Ar+ ion irradiation

TL;DR

This study demonstrates the formation of self-organized InP nano dots via low-energy Ar+ ion sputtering, analyzing their morphology and optical properties, and revealing size evolution and phonon confinement effects.

Contribution

It introduces a method to create and characterize self-organized InP nano dots with controlled size and morphology using ion sputtering.

Findings

Nano dots range from 10 to 100 nm in size.

Nano dot size and height increase up to a critical sputtering time.

Beyond the critical time, nano structures break down and become less uniform.

Abstract

We report formation of self organized InP nano dots using 3 keV Ar+ ion sputtering, at $15^\circ$ incidence from surface normal, on InP(111) surface. Morphology and optical properties of the sputtered surface, as a function of sputtering time, have been investigated by Scanning Probe Microscopy and Raman Scattering techniques. Uniform patterns of nano dots are observed for different durations of sputtering. The sizes and the heights of these nano dots vary between 10 to 100 nm and 20 to 40 nm, respectively. With increasing of sputtering time, t, the size and height of these nano dots increases up to a certain sputtering time $t_c$. However beyond $t_c$, the dots break down into smaller nanostructures, and as a result, the size and height of these nanostructures decrease. The uniformity and regularity of these structures are also lost for sputtering beyond $t_c$. The crossover behavior is also observed in the rms surface roughness. Raman investigations of InP nano dots reveal optical phonon softening due to phonon confinement in the surface nano dots.