Electrical and Optical Properties of Radio-Frequency-Sputtered Thin Films of (ZnO)₅In₂O₃

c -Axis oriented thin films of (ZnO) 5 In 2 O 3 of 0.5 μm thickness were deposited on glass substrates by a radio-frequency-sputtering method. The thin films had dense columnar structures and were highly transparent in the ultraviolet−visible region, simultaneously showing low electrical resistivity. The refractive index was about 2. The lowest resistivity, 1.3 × 10 - 3 Ω cm at room temperature, was obtained by reducing the deposited film at 540 °C in N 2 containing 3.4% H 2 . The corresponding carrier concentration and Hall mobility were 1.9 × 10 20 cm - 3 and 25.6 cm 2 /Vs, respectively. Detailed analyses of the optical transmittance spectra gave rise to the intrinsic band gap and the reduced mass of carriers to be 3.12 eV and 0.67 m 0, respectively.