Comparative study of Al-doped ZnO films deposited by sol–gel and by sputtering using a sintered target from ZnO nanoparticles synthesized by sol–gel

Al-doped zinc oxide (ZnO) films were deposited on glass substrates by radio frequency magnetron sputtering using a sintered target of nanoparticles synthesized by sol–gel. The films were characterized using X-ray diffraction, scanning electron microscopy, the four-point probe method for resistivity, energy dispersive X-ray spectroscopy and photoluminescence. The X-ray diffraction patterns showed a hexagonal structure corresponding to the wurtzite phase for all the films, nanoparticles, and sintered targets. The films deposited by sputtering showed a highly preferred orientation to the (002) plane. These films were compared structurally and electrically to those deposited by the sol–gel method. Photoluminescence spectra show a decrease in intensity due to the reduction of defects by the incorporation of Al as dopant in the ZnO films deposited by the both methods (sol–gel and sputtering). The Al-doped ZnO films deposited by sputtering reached resistivity of 0.1 Ω cm and those deposited by sol–gel reached a resistivity of 1.24 Ω cm. The physical properties of these films show potential for application in devices like sensors and biosensors.