Al doped zinc oxide thin films with different electrical and optical properties have been developed by both non-reactive and reactive rf-magnetron sputtering in Ar and Ar+H₂ atmospheres, respectively. The thin films prepared under Ar+H₂ gas ambient at substrate temperatures of 100°C and 300°C show high conductivity and improved IR-reflectivity. The lowest resistivity obtained is 4.5×10⁻⁴ Ω cm at 300°C. The transmission of the ZnO : Al film in the visible range is above 90% and that at 1400 nm is only 3.2%. Most of the IR-region is thus reflected. The carrier concentration of this transparent, conducting ZnO film prepared under Ar+H₂ atmosphere is 2.3×10²¹ cm⁻³. Tranmission electron micrographs reveal that the average crystallite of the sample deposited under Ar+H₂ ambient is smaller compared to those prepared under Ar ambient. The 100, 002 orientations of ZnO with wurtzite structure are observed from transmission electron diffraction pattern.

73.61.Ga II-VI semiconductors

68.37.Lp Transmission electron microscopy (TEM)

61.05.J- Electron diffraction and scattering

78.66.Hf II-VI semiconductors

81.15.Cd Deposition by sputtering

Semiconductors

Surfaces, interfaces and thin films

Issue 2 (21 January 2003)

Received 23 July 2002

Published 30 December 2002