Effect of Film Thickness on Photoelectrochemical Performance of SnO2 Prepared via AACVD

Abstract

Tin (IV) oxide (SnO2) is a stable semiconductor and has been used in a wide range of applications. In this work, aerosol-assisted chemical vapor deposition (AACVD) technique is employed to deposit SnO2 thin film with different layer thicknesses by controlling the deposition time. The morphological and optical properties of SnO2 layer are investigated thoroughly to understand the relationship between the deposition time and SnO2 performance in photoelectrochemical cells. The bandgap energy of all SnO2 thin films is determined to be 3.65 eV. However, from linear sweep voltammetry (LSV) analysis, it is found that SnO2 layer deposited for 15 min, which produced a layer with thickness of about 50 nm, showed the best photocurrent performance (30.7 µA cm−2 at 1.0 V vs. Ag/AgCl) compared to their thinner or thicker counterparts. The right thickness enables the formation of a film with complete surface coverage, which effectively prevents current leakage and allows optimum light absorption. Besides, electrochemical impedance spectroscopy (EIS) analysis confirms that 50 nm thick SnO2 layer possesses fastest electron transfer property compared to thicker or thinner layers.