The low temperature synthesis of Al doped ZnO films on glass and polymer using pulsed co-magnetron sputtering: H2 effect

It has been reported that a small amount of hydrogen in argon plasma induces an increase in the crystallite size of the as-deposited films. In addition, control of the hydrogen partial pressure is expected to improve the carrier mobility by increasing the crystallinity of the film (larger crystal size and lower grain boundary effects). Al doped ZnO (AZO) films were deposited by co-CFUBM (closed field unbalanced magnetron) sputtering. The ultimate aim was to deposit transparent films on a polymer substrate with a low electrical resistivity. Therefore, the structural, optical and electrical properties of AZO films were investigated as a function of the hydrogen partial pressure. A minimum resistivity and maximum transparency of 8 × 10− 4 Ω cm and 88.1% were obtained, respectively. A critical PH2 was expected to improve the carrier mobility by increasing the crystallinity of the film. However, above this value, conductivity reduced due to the formations of oxides such as ZnO and Al2O3 in the AZO films.