Formation of nanoripples on ZnO flat substrates and nanorods by gas cluster ion bombardment.

Xiaomei Zeng,Xiangheng Xiao,Alexander Tolstogouzov,Bin Xing,Chuansheng Liu,Rakhim Rakhimov,Wenbin Zuo,Vasiliy Pelenovich,Dejun Fu

doi:10.3762/bjnano.11.29

Abstract

In the present study Ar+ cluster ions accelerated by voltages in the range of 5–10 kV are used to irradiate single crystal ZnO substrates and nanorods to fabricate self-assembled surface nanoripple arrays. The ripple formation is observed when the incidence angle of the cluster beam is in the range of 30–70°. The influence of incidence angle, accelerating voltage, and fluence on the ripple formation is studied. Wavelength and height of the nanoripples increase with increasing accelerating voltage and fluence for both targets. The nanoripples formed on the flat substrates remind of aeolian sand ripples. The ripples formed at high ion fluences on the nanorod facets resemble well-ordered parallel steps or ribs. The more ordered ripple formation on nanorods can be associated with the confinement of the nanorod facets in comparison with the quasi-infinite surface of the flat substrates.

Highlights

The formation of self-assembled nanoscale surface structures using off-normal ion irradiation has a few advantages over traditional photolithography techniques, i.e., the absence of fundamental restrictions for the size reduction of the formed structures and cost-effective production
Their large flat surface allows to determine the main dependencies of ripple formation on the gas cluster ion beams (GCIB) parameters
scanning electron microscope (SEM) and atomic force microscope (AFM) images shown in Figure 2 and Figure 3, respectively, present the surface morphology of the substrates before and after Ar cluster bombardment at different incidence angles, θ = 0–80°

Summary

Introduction

The formation of self-assembled nanoscale surface structures using off-normal ion irradiation has a few advantages over traditional photolithography techniques, i.e., the absence of fundamental restrictions for the size reduction of the formed structures and cost-effective production. Toyoda et al have studied the influence of incidence angle and cluster size on the ripple formation on Au surfaces.

Results

Conclusion