Structural, electrical and optical properties of transparent Zn1 − xMgxO nanocomposite thin films

Zn1 − xMgxO thin films of various Mg compositions were deposited on quartz substrates using inexpensive ultrasonic spray pyrolysis technique. The influence of varying Mg composition and substrate temperature on structural, electrical and optical properties of Zn1 − xMgxO films were systematically investigated. The structural transition from hexagonal to cubic phase has been observed for Mg content greater than 70 mol%. AFM images of the Zn1 − xMgxO films (x = 0.3) deposited at optimized substrate temperature clearly reveals the formation of nanorods of hexagonal Zn1 − xMgxO. The variation of the cation–anion bond length to Mg content shows that the lattice constant of the hexagonal Zn1 − xMgxO decreases with corresponding increase in Mg content, which result in structure gradually deviating from wurtzite structure. The tuning of the band gap was obtained from 3.58 to 6.16 eV with corresponding increase in Mg content. The photoluminescence results also revealed the shift in ultraviolet peak position towards the higher energy side.