Keywords: ZnO thin films, zinc oxide, aluminium doping, magnesium doping, sol–gel route, photocurrent, transparent thin films, spin coating, glass substrates, structural properties, surface morphologies, optical transparency, optical band gap, photosensitivity, nanoelectronics, nanotechnology
Preparation, characterisation and photocurrent study of sol–gel–derived Al, Mg–doped ZnO transparent thin films
In this work, sol–gel spin–coating was employed to prepare ZnO, Al–doped ZnO (AZO) and Mg–doped ZnO (MZO) thin films onto glass substrates. Structural properties and surface morphologies of as–prepared films were characterised by X–ray diffraction (XRD) and scanning electron microscope (SEM) while their optical properties were scrutinised from their transmission spectra measured by UV–VIS spectrophotometer. Their optical responses and sensitivity of the films were investigated by photocurrent spectroscopy. The XRD and SEM results show that the crystallinity and physical structure of as–prepared films are highly affected by Al and Mg doping. UV–VIS spectrophotometer results suggest that Mg and Al dopants could not only improve their optical transparency but also significantly cause the blue–shift in optical band gap of ZnO films. In addition, the enhancement in photosensitivity of ZnO films can be attained by specific Al and Mg doping content.