EFFECT OF THICKNESS ON THE PROPERTIES OF In-DOPED ZnO THIN FILMS PREPARED BY RF MAGNETRON SPUTTERING

Abstract

In-doped zinc oxide ( ZnO:In ) thin films with thickness from 157 nm to 592 nm have been deposited on glass substrates by radio frequency (RF) magnetron sputtering. The effect of the film thickness on the structural, electrical and optical properties of ZnO:In thin films has been investigated. It is found that the films are hexagonal wurtzite structure with c-axis perpendicular to the substrate, and with increasing thickness, the crystallinity, the grains size and the conductivity of the films increases, but the strains along c-axis and the transmittance decrease. The decrease of the resistivity in a thicker film is attributed to the slight increase of the carrier concentration and the significant increase of Hall mobility. The transmittance of all the films is over 80% in the visible region (400–800 nm) and the band gap decrease with the increase of film thickness. The film with the thickness of around 303 nm has the resistivity of 6.07 × 10-3 Ω⋅ cm and the transmittance of 90% in the visible range. Based on the good conductivity and high transmittance, the ZnO:In films prepared by magnetron sputtering can be regarded as a potential transparent electrode.