Influence of doping precursor on band gap and morphologies of sol‐gel deposited ZnMgO thin films

Abstract

AbstractZn1–xMgxO thin films were deposited by sol–gel route on p–type Si (100) and quartz substrates. It is ob‐served that the incorporation of Mg and morphological features of the sol–gel derived Zn1–xMgxO thin films extremely depend upon the selection of doping (Mg) precursor salts. Investigation of different doping precursors such as magnesium acetate, magne‐sium chloride and magnesium nitrate have been carried out. Zn1–xMgxO (x = 0.15) thin films deposited us‐ing each doping source were annealed at 300, 500, 700 and 900 °C in the presence of oxygen for one hour. The results showed that the magnesium nitrate required lower annealing temperature and provided good quality of films, However traces of N were observed in the films. The surface morphology and microstructure of the depos‐ited thin films were analyzed by atomic force microscopy. The crystallite dimension, shape and the growth rate were found to be significantly affected by dopant precursors. The chemical compositions were determined by elemen‐tal dispersive spectra. The band gap modulation is stud‐ied by varying the magnesium content from x = 0.00 to 0.40 for each type of salt for Mg doping. The Zn1–xMgxO films deposited using magnesium chloride exhib‐ited poor band gap modulation and lower quality of mi‐crostructure. The films deposited using magnesium ace‐tate exhibited minimum defects, good crystallinity and higher band gap modulation. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)