Template based room temperature growth of high density CdS nanowires from aqueous electrolyte using high frequency alternating current

Abstract

High quality CdS nanowires (NWs) are grown at room temperature by electrochemical deposition into the pores of prepared porous alumina templates (PATs) from alkaline aqueous electrolyte solution (pH = 8.5) containing Cd²⁺ and S₂O₃ ²⁻, using high frequency (200 Hz) alternating current (ac, 21 V_rms). PATs with hexagonally ordered nanoporous columns are prepared using relatively simple and faster single step anodizing at 30 V_dc in 0.24 M oxalic acid. The room temperature synthesis of NWs from aqueous solution using ac voltage simplifies the growth process as well as makes it an inexpensive approach for the fabrication of CdS NWs in large density. Atomic force microscopy and scanning electron microscopy (SEM) confirm the formation of spatially regular and well-arranged hexagonal porous structures. SEM further shows that diameter of grown CdS NWs lie in the range ~ 30–50 nm. Raman spectroscopy and X-ray diffraction of as deposited and annealed PAT–CdS nanowires composites confirm the formation of high crystalline quality CdS NWs having hexagonal wurtzite crystal structure. The preparation method and possible mechanism for the synthesis of CdS NWs is discussed. The deposition method can be generalized to a wide range of semiconductors.