Optical and hall properties of Al-doped ZnO thin films fabricated by pulsed laser deposition with various substrate temperatures

The 3 wt% Al-doped zinc oxide (AZO) thin films were fabricated on quartz substrates at a fixed oxygen pressure of 200 mTorr with various substrate temperatures (room temp. similar to 500 A degrees C) by using pulsed laser deposition in order to investigate the microstructure, optical, and electrical properties of AZO thin films. All thin films were shown to be c-axis oriented, exhibiting only a (002) diffraction peak. The AZO thin film, fabricated at 200 mTorr and 400 A degrees C, showed the highest (002) orientation and the full width at half maximum (FWHM) of the (002) diffraction peak was 0.42A degrees. The c-axis lattice constant decreased with increasing substrate temperature. The electrical property indicated that the highest carrier concentration (1.27 x 10(21) cm(-3)) and the lowest resistivity (6.72 x 10(-4) Omega cm) were obtained in the AZO thin film fabricated at 200 mTorr and 400 A degrees C. The optical transmittance in the visible region was higher than 80 %. The Burstein-Moss effect, which shifts to a high photon energy, was observed.