Enhanced dopant incorporation into SnO2 thin films based on dual source spray pyrolysis deposition process

Abstract

Recently, SnO2 has attracted much attention for optoelectronic applications in infrared (IR) spectral ranges due to its high transparency in the ultraviolet to IR wavelength spectral range and high electrical conductivity. The transition metal-doped SnO2 based on the ultrasonic-assisted spray pyrolysis deposition (SPD) method has been widely used for various optoelectronic applications. However, the SPD process has suffered from inefficient doping of foreign elements due to difficulties in controlling the single precursor source solutions and complicated solution dynamics. To overcome these problems, the co-SPD process supplying the host and dopant solutions separately was suggested for the deposition of the Zn-doped SnO2 thin films. The Zn-doped SnO2 thin films deposited by co-SPD showed insulating electrical properties due to the efficient incorporation of the Zn element as an oxygen vacancy scavenger and acceptor to annihilate the free charge carriers. Also, the Zn-doped SnO2 films showed an IR transmittance of over 80 %, maintained at a temperature of up to 500 ℃. Thus, the co-SPD process can be a promising approach to achieve highly doped oxide films with high IR transmittance even at elevated temperatures.