Search

ZnO thin films (thickness ∼ 400 nm) were prepared at different oxygen content (O2) by radio frequency (rf) sputtering method. Crystal structure and optical properties of these films were investigated by x-ray diffraction (XRD) and UV-VIS-NIR spectrophotometer, respectively. XRD measurement suggests that all films have hexagonal wurtzite structure. The transparency in the visible region of all the film is more than 90%. The optical absorption edge was described using the direct transition model proposed by Tauc and the optical band gap was calculated from the absorption coefficient by Tauc's extrapolation procedure. The value of optical band gap was decreased with increase in the O2 content; due to Burstein-Moss shift. [ABSTRACT FROM AUTHOR]

Transparent oxide semiconductor, a-GaInZnO, thin films were deposited by radio frequency (RF) magnetron sputtering at different oxygen/Argon (O2/Ar) flow ratio on glass substrates. The effect of oxygen content was studied on the transmittance and optical band gap of these thin films. The average transmittance in the visible region decreased with increase in the oxygen content. The optical band gap also decreased with increase in the oxygen content. With increasing oxygen content, the absorption edge shifted to the longer wavelength due to the decreased Burstein-Moss effect. [ABSTRACT FROM AUTHOR]