Letter
Concentration-dependent behavior of hydrogen in Al-doped ZnO thin films
Lin Zhaoa, Guang-Jie Shaoa, b, 
, 
, Xiu-Juan Qina, b and Si-Hui-Zhi Hana
Received 26 January 2011;
revised 8 April 2011;
accepted 10 April 2011.
Available online 20 April 2011.
Abstract
The Al-doped ZnO thin films were synthesized by aerosol-assisted chemical vapor deposition. The concentration-dependent behavior of hydrogen in the films was discussed, finding that as hydrogen is introduced at a relatively low level, it tends to take the oxygen vacancy site and form a hydrogen-oxygen vacancy complex which behaves as a shallow donor, on the other hand it reduces the solubility of the substitutional Al; then higher hydrogen concentration results in the formation of H2 neutral molecular complex.
