Codoping in ZnO using GaN by pulsed laser deposition

We report on the codoping of Ga and N into ZnO films by pulsed laser deposition with ZnO:GaN targets of different concentrations. The effect of GaN dopant on the structural, optical and electrical properties have been investigated. The X-ray diffraction (XRD) measurements show that for the GaN concentration up to 0.8 mol%, the full width at half maximum (FWHM) of (0 0 2) peak significantly reduces and thereby improves the crystallinity of the films while for 1 mol% the FWHM increases. For the GaN-doped films, the photoluminescence (PL) spectra show only a strong near band edge (NBE) emission and the deep level emissions are almost undetectable, indicating that GaN doping considerably suppresses the defect related emissions. The glow discharge mass spectroscopy (GDMS) spectra confirm the presence of Ga and N in the grown films. Our Hall measurements show that all the GaN-doped ZnO films are n-type, indicating that N acceptors are not sufficient to compensate the donors. The carrier concentrations have been increased till 0.8 mol% of GaN and decreased for 1 mol% GaN-doped film.