Influence of background gas atmosphere on formation of Cr 2 O 3 thin films prepared by pulsed laser deposition

Abstract

Cr₂O₃ thin films deposited on Si (100) and glass substrates by pulsed laser deposition using Cr₃C₂ target were investigated. The films were deposited at base pressure (4 × 10⁻⁵ mbar) and at different gas atmospheres, such as argon and methane. X-ray diffraction and X-ray photoelectron spectroscopy studies of the films showed only Cr₂O₃ phase formation irrespective of the background gas environment during deposition. The films deposited on Si (100) substrates contain nanocrystallites with the size varying in the range 24–72 nm, while that on glass substrates contain crystallites of size varying from 19–56 nm. The ultraviolet visible spectroscopy studies showed that the films are transparent in the visible region. The band gap of the deposited films were calculated using Tauc plot and it was found to exhibit direct band gap in the range 3·10–3·60 eV. The band gap was minimum (3·10 eV) with the argon gas atmosphere, while it is 3·60 eV in methane atmosphere.