Carrier concentration induced band-gap shift in Al-doped Zn1−xMgxO thin films

Abstract

Transparent conducting Al-doped Zn1−xMgxO thin films were grown on glass substrates by chemical vapor deposition. The resistivity could be lowered to 10−3Ωcm with optical transmittance above 85% in visible regions. The influence of carrier concentration on band-gap shift in Zn1−xMgxO alloys was systematically studied. The shift of energy gap could be fully explained by the Fermi-level band filling and band-gap renormalization effects. As the Mg content increased, the electron effective masses in Zn1−xMgxO (x=0–0.21) alloys increased from 0.30m0 to 0.49m0. The Al-doping efficiency was reduced with the increase in alloy composition.