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

Abstract

Tin (IV) oxide (SnO 2 ) 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 SnO 2 thin film with different layer thicknesses by controlling the deposition time. The morphological and optical properties of SnO 2 layer are investigated thoroughly to understand the relationship between the deposition time and SnO 2 performance in photoelectrochemical cells. The bandgap energy of all SnO 2 thin films is determined to be 3.65 eV. However, from linear sweep voltammetry (LSV) analysis, it is found that SnO 2 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 SnO 2 layer possesses fastest electron transfer property compared to thicker or thinner layers.