| 초록 |
Mg and Ga co-doped ZnO (MxGyZzO, x+y+z=1, x=0.05,y=0.02 and z=0.93) thin films were prepared on glass substrates by RF magnetron sputtering technique with different working pressures from 3 to 9mTorr at 400oC. The effect of different working pressures on the structural, morphological, electrical, and optical properties of MGZO thin films were investigated. The X-ray diffraction patterns showed that all the MGZO thin films were grown as a hexagonal wurtzite phase with c-axis preferred orientation without any secondary phase. The diffraction peaks from (0002) plane of ZnO:Ga:Mg thin films were enhanced with increasing the different pressures. The cross-sectional field emission scanning electron microscopy images of MGZO thin films showed that all the thin films have a columnar structure and thickness increased with increasing pressures. The MGZO thin film deposited at the working pressure of 7mTorr showed the best electrical characteristics in terms of the carrier concentration (2.7ｘ1020 cm-3), charge carrier mobility (7.5 cm2V-1s-1), and a minimum resistivity (2.28ｘ10-3 Ωcm). UV-visible spectroscopy studies showed that the MGZO thin films have a high transmittance over 80 % in the visible region and the absorption edge of MGZO thin films were very sharp and shifted toward lower wavelength side from 340 nm to 320 nm with increasing the working pressures. The band gap energy of MGZO thin films were wider from 3.60 eV to 3.72 eV with increasing the working pressures. |
