Sonolectrochemically Deposited Nanostructured Copper Thin Films at Low Temperatures:Growth Kinetics and Nucleation Behaviour

Abstract

Electrodeposition of copper are studied both in presence and absence of ultrasound at low temperatures (25°C,−2.5°C and −4°C). The deposits are analyzed and characterized by cyclic voltammetry (CV), chronoamperometry (CA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The diffusion coefficient along with the nuclei number density gradually increases under ultrasonic irradiation. The silent nucleation phenomenon has a transition from instantaneous to progressive nucleation in comparison to the instant appearance under insonation with decreasing temperature. Ultrasound also assists the secondary nucleation on the preexisting grains. The XRD analysis of the films confirms the copper crystallinity. XRD measurement along with the AFM analysis confirms the nano grains in the films. Good surface coverage and crystallinity under insonation can be observed from the SEM morphologies. The 3D topographical AFM analysis of the sonicated substrates further compliments the SEM analysis.