Photoelectrochemical Deposition of Silicon–Carbon Layer on P-Type Semiconductors and Aluminum–Copper Alloy in Ionic Liquid

Abstract

Electrochemical deposition of silicon at room temperature is problematic due to the intrinsically low conductivity of the deposits. This study reports the photoelectrochemical (PEC) deposition of silicon (Si) and silicon–carbon (Si–C) layers from an ionic liquid at 40 °C using silicon tetrachloride (SiCl4) as a silicon precursor. Amorphous layers are deposited on p-type silicon (p-Si), p-type gallium arsenide (p-GaAs), and aluminum–copper alloy AA2024. The semiconductor substrates are activated by white LED illumination, which generates photoelectrons, thereby making the substrate conductive with respect to the cathodic reaction. The photoresponsiveness of the deposits is proven by the light-induced photocurrents on an optically inactive substrate made of the alloy AA 2024. The proposed method paves the way for the electrochemical modification of semiconductors and metals with Si and Si–C structures, which are applicable in various fields, such as batteries, anti-corrosion coatings, photovoltaics, or PEC electrodes for hydrogen production.