LOW TEMPERATURE FABRICATION AND PHYSICAL PROPERTIES OF 5 at.% Ga-DOPED ZnO FILMS FOR TRANSPARENT ELECTRODE APPLICATIONS

Abstract

Transparent conductive 5 at.% Ga-doped ZnO (GZO) thin films are deposited on a glass substrate by an asymmetrical bipolar-pulsed DC magnetron sputtering at various substrate temperatures. All the GZO films have nanocrystalline structure and compact surface morphology. A highly c-axis oriented GZO film was grown perpendicular to the substrate at the 200 degrees C. The measured work function of GZO film deposited at 200 degrees C shows slightly lower value of 4.37eV than a commercial ITO film of 4.6eV. The GZO film showed the lowest sheet resistance of 35 Omega/square, a carrier concentration of 1.2 x 10(21) cm(-3), a mobility of 9.9 cm(2)/Vs, and high optical transmittance of over 85% in the visible range. It indicates that the GZO films at 200 degrees C can be promising as an alternative to ITO thin film for transparent electrode applications.