Growth and characterization of undoped Al doped Zinc Oxide ZnO nanostructured thin films by non conventional sol gel method for PN junction diode and second order nonlinear optical application

Abstract

newline In the present work Zinc Oxide (ZnO) thin films were growth on glass and Silicon (Si) newlinesubstrates by non-conventional sol-gel method taking its powder precursors. This nonconventional newlinemethod has the advantage that its precursor (ZnO powder) is extremely newlinechemically and thermally stable. The effects of annealing temperature, annealing time, newlinesolution aging time and doping by Aluminum on the structural, optical and electrical newlineproperties were investigated. Aluminum nitrate was used as a source for Al ions. XRD was newlineused to characterize the structure of obtained thin films, Debye-Scherrer formula was used newlineto estimate the particle size. FESEM was used to study the morphological properties of the newlineobtained thin films. Ultraviolet-Visible Spectroscopy system was used in the optical study newlineto measure the transmittance. It was found that ZnO thin film can be grown without the newlinecalcinations process and hence found to be very useful for applications like PN newlineheterojunction diodes and second harmonic generation. Increase of aging time from 1 day newlineto 13 days has led to increase the film thickness of ZnO films from 165 nm to 556 nm newlinewhich means an increase by 337% with the same 6 number of dips. The growth rate was newlinefound to be 34 nm per day of aging time. newlineThis indicates the importance of aging time in control of the growth process and film newlinethickness. The significance of our study is that despite thickness increasing by 337% the newlinetransmittance decreased by 6% only. The electrical properties mainly conductivity, carrier newlineconcentration and mobility were studied by using the Hall Effect measurement system. newlineFrom the electrical effect study, it was observed that the carrier concentrations and newlineconductivity were found to be 962 and 118 times respectively higher than the pure samples. newlineThis observation refers to capable of using AZO thin films prepared by our method in newlinephotoelectronic applications like heterojunction diodes and solar cells. newlineFemtosecond laser pulses with 1030 nm wavelength was used for Second Harmonic newlineGeneration (SHG)