Synthesis and optical properties of CuS nanowires fabricated by electrodeposition with anodic alumina membrane

Abstract

Crystalline CuS nanowire arrays have been successfully fabricated by an AC with DC electrodeposition from aqueous solutions of dimethylsulfoxide solution containing copper chloride and elemental sulfur into oxalic anodic alumina membranes (AAM). The results of X-ray diffraction show that the as-synthesized nanowires are crystalline with highly preferential [100] orientation and show the hexagonal structure. Scanning electron microscopy indicates that the ordered CuS nanowire arrays are completely embedded into AAM. These nanowires have uniform diameters of approximately 60 nm, and their lengths are up to tens of micrometers. The absorbance in UV–Vis spectrum might be attributed from the varied copper sulfide phase. The high energy absorbance might be due to the characteristic of Cu₂S composition of the few amounts in our sample. The broad and strong absorbance in the near-IR region might be due to the characteristic of CuS.

Introduction

One-dimensional nanostructures have become the focus of intense research, because they provide a good system for investigating the dependence of electrical, optical, and thermal transport or mechanical properties on dimensionality and size confinement [1], [2]. As an important semiconductor material, copper sulfide has been found many applications for its metal-like electrical conductivity [3], chemical-sensing capability [4] and ideal characteristics for solar energy absorption [5]. There are many ways to prepare nanosized copper sulfide.

Some methods, such as soft colloidal templates [6], in situ template-controlled (ISTC) method [7], microwave irradiation [8], template-free synthesis [9], biomolecule-assisted hydrothermal approach [10], solid-state reaction route [11], have been utilized to prepare one-dimensional CuS nanorods and nanowires, searching for a simple synthetic route is still an interesting subject worthy of further exploration.

Herein we synthesize CuS nanowire by electrodepositing with the template method, a way for preparing one dimensional nanostructural materials, which entails fabricating the desired material within the pores of a template membrane [12], [13], [14], [15]. The use of either direct current or alternate current for the nanowire deposition of a range of materials (such as CdSe, SnO₂, TiO₂, InO₂, Bi₂S₃ etc) have already been shown to produce well ordered crystallized highly dense nanowire arrays.

In this report, we use an AC and DC electrodeposition process at the same time to fabricate CuS nanowire arrays in AAM templates from a dimethylsulfoxide (DMSO) solution containing copper chloride and elemental sulfur. So far this is the first work to have successfully used electrodeposition to fabricate aligned CuS nanowire arrays and study its properties.