A facile growth of spray based ZnO films and device performance investigation for Schottky diodes: Determination of interface state density distribution

This paper reports on the study of ZnO films grown by chemical spray pyrolysis on glass and Si substrates at temperatures of 300, 350 and 400 degrees C and on the performances of the corresponding Au/n-ZnO Schottky diodes. XRD measurements have shown that all films are in single phase and have a wurtzite crystal structure. Microstructural properties such as lattice constants (a = b not equal c), unit cell volume, texture, dislocation density, standard deviation have been determined. The crystal size and the microstrain have also been calculated by taking X-ray line broadening profile into account. Besides, the optical features have been investigated by UV-Vis measurements. The optical band gap was found dependent on the temperature of the substrate during film growth and decreased from 3.28 to 3.24 eV in case of films grown at 300 and 400 degrees C, respectively. Electrical characterizations of Au/n-ZnO Schottky barrier diodes have been investigated using the current-voltage (I-V) and the capacitance-voltage (C-V) measurements. Results show that the ideality factor firstly increased for the film grown at 350 degrees C, then decreased for the film grown at 400 degrees C. Also, barrier height decreased with the increase of substrate temperature. This behaviour has been attributed to the inhomogeneous nature of barrier height, to variation of interface states and to the formation of a new phase on ZnO surface. (C) 2017 Elsevier B.V. All rights reserved.