Structural, optical, and electrical properties of low-concentration Ga-doped CdO thin films by pulsed laser deposition

Abstract

CdO thin films with low Ga doping concentrations were deposited on low-cost glass substrates by pulsed laser deposition. The influence of Ga doping concentration on structural, electrical, and optical properties of CdO thin films was studied. The Ga-doped CdO thin films show decreasing plasma wavelength and resistivity when increasing doping concentration, and the widening optical gap varies from 2.49 to 2.85 eV with the Ga doping concentration increasing from 0.2 to 1.2 at% due to Moss–Burstein effect. When Ga doping concentration in CdO thin films was controlled at low level from 0.6 to 1.0 at%, the films achieved both high conductivity (~10−4 Ω·cm) and high transmittance up to the infrared region (>1600 nm), which demonstrates good potential as an ideal transparent conductor of full-spectrum photovoltaic devices.