Effect of annealing atmosphere on the electrical and optical properties of sol-gel derived Al doped Zn1 − xMgxO thin film

Aluminum doped Zn1 − xMgxO (AZMO) thin film has been developed on glass substrate by a sol-gel process with two-step annealing. Annealing atmosphere plays an important role in improving the electrical and optical properties of AZMO thin film at each step. It was found that the first step annealing in nitrogen increased carrier concentration, and the second step annealing in forming gas with a Glass Cover (GC) contributed to the improvement of Hall mobility. An optimum H2 concentration in forming gas exists for decreasing the resistivity of AZMO thin film when the second step annealing in forming gas was conducted without the GC. An AZMO thin film with a resistivity of 8.4 × 10− 3 Ω·cm (carrier concentration of 4.0 × 1019 cm− 3, Hall mobility of 18.6 cm2/V·s, optical bandgap energy of 3.65 eV) was obtained.