Investigation of some physical properties of ZnO nanofilms synthesized by micro-droplet technique

Abstract In this paper, ZnO nanocrystals were synthesized using a simple micro-droplets technique from a solution prepared by dissolving zinc acetate di-hydrate [Zn(CH3COO)2, 2H2O] in methanol. Microdroplets were deposited on glass substrates heated at 100 °C, the obtained samples of ZnO films were investigated by XRD, AES, AFM, ellipsometry and PL. XRD patterns reveal the wurtzite structure of ZnO where the lattice parameters a and c, calculated from XRD signals, show a nanometric character of ZnO nanoparticles. The chemical composition of ZnO film surfaces was verified by Auger electron spectroscopy (AES). From Auger signals, oxygen (O-KLL) and zinc (Zn-LMM) Auger transitions indicate well the presence of Zn-O bonding. The surface topography of the samples was measured by atomic force microscopy (AFM) where ZnO nanoparticles of average size ranging between 20 and 80 nm were determined. Some optical properties as dielectric constants, refractive index, extinction coefficient as well as the optical band gap were determined from ellipsometry analysis. The dispersion of the refractive index was discussed in terms of both Cauchy parameters and Wemple & Di-Dominico single oscillator model. The photoluminescence (PL) measurements exhibited two emission peaks. The first at 338 nm, corresponding to the band gap of ZnO, is due to excitonic emission while the second around 400 nm, is attributed to the single ionized oxygen vacancies.

[1]  A. Ashour,et al.  Physical properties of ZnO thin films deposited by spray pyrolysis technique , 2006 .

[2]  Maria Dinescu,et al.  ZnO thin film deposition by laser ablation of Zn target in oxygen reactive atmosphere , 1996 .

[3]  M. Didomenico,et al.  Dielectric behavior of ferroelectric BaMF4 above room temperature , 1969 .

[4]  M. Amlouk,et al.  Some physical investigations on hexagonal-shaped nanorods of lanthanum-doped ZnO , 2015 .

[5]  L. Fang,et al.  Effect of annealing temperature on the structure and optical properties of In-doped ZnO thin films , 2009 .

[6]  A. Boukhachem,et al.  Structural, opto-thermal and electrical properties of ZnO:Mo sprayed thin films , 2012 .

[7]  K. Boubaker,et al.  Europium incorporation dynamics and some physical investigations within ZnO sprayed thin films , 2016 .

[8]  K. Washio,et al.  Thermal stability of conductive and transparent V-doped ZnO thin films , 2014 .

[9]  A. Labidi,et al.  Some physical investigations on silver-doped ZnO sprayed thin films , 2015 .

[10]  S. Pearton,et al.  Magnetization dependence on electron density in epitaxial ZnO thin films codoped with Mn and Sn , 2005 .

[11]  P. P. Sahay,et al.  Al-doped ZnO thin films as methanol sensors , 2008 .

[12]  S. H. Wemple.  Optical oscillator strengths and excitation energies in solids, liquids, and molecules , 1977 .

[13]  Simon J. Henley,et al.  The growth of transparent conducting ZnO films by pulsed laser ablation , 2004 .

[14]  W. Jones,et al.  Thermal stability of ZnO nanoparticle bound organic chromophores , 2016 .

[15]  D. Aspnes.  Approximate solution of ellipsometric equations for optically biaxial crystals. , 1980, Journal of the Optical Society of America.

[16]  C. Bunn,et al.  The lattice-dimensions of zinc oxide , 1935 .

[17]  M. Ghamnia,et al.  Effects of potassium incorporation on the structural, optical, vibrational and electrical properties of NiO sprayed thin films for p-type optical windows , 2016 .

[18]  R. Swanepoel,et al.  XRD analysis of ZnO thin films prepared by spray pyrolysis , 1997 .

[19]  M. Nakayama,et al.  Optical properties of high-quality ZnO thin films grown by a sputtering method , 2005 .

[20]  Y. Bando,et al.  Size‐Tailored ZnO Submicrometer Spheres: Bottom‐Up Construction, Size‐Related Optical Extinction, and Selective Aniline Trapping , 2011, Advanced materials.

[21]  Jian Xu,et al.  Preparation and characterization of Al doped ZnO thin films by sol–gel process , 2012 .

[22]  K. Kushiya,et al.  MOCVD-ZnO windows for 30cm×30cm CIGS-based modules , 2003 .

[23]  A. Rennie,et al.  Use of wide-angle X-ray diffraction to measure shape and size of dispersed colloidal particles. , 2009, Journal of colloid and interface science.

[24]  L. Ono,et al.  Effects of annealing on properties of ZnO thin films prepared by electrochemical deposition in chloride medium , 2010 .

[25]  R. Azzam,et al.  Ellipsometry and polarized light , 1977 .

[26]  M. Kahlaoui,et al.  Physical investigations on MoO3 sprayed thin film for selective sensitivity applications , 2014 .

[27]  Wenqin Peng,et al.  Synthesis and Structures of Morphology-Controlled ZnO Nano- and Microcrystals , 2006 .

[28]  N. Muensit,et al.  Optical and photocatalytic properties of La-doped ZnO nanoparticles prepared via precipitation and mechanical milling method , 2013 .

[29]  Yang Li,et al.  Feedforward control of a closed-loop piezoelectric translation stage for atomic force microscope. , 2007, The Review of scientific instruments.

[30]  S. Belgacem,et al.  Propriétés optiques des couches minces de SnO2 et CuInS2 airless spray , 1990 .

[31]  Young-Chon Kim,et al.  In-Situ Cure Monitoring of Wind Turbine Blades by Using Fiber Bragg Grating Sensors and Fresnel Reflection Measurement , 2015, Sensors.

[32]  Thomas Höche,et al.  Transparent semiconducting ZnO:Al thin films prepared by spray pyrolysis , 1999 .

[33]  Q. Fu,et al.  ZnO thin films deposited by a CVT technique in closed ampoules , 2009 .

[34]  T. Sinha,et al.  Dielectric relaxation of ZnO nanostructure synthesized by soft chemical method , 2010 .

[35]  Jacques I. Pankove,et al.  Optical Processes in Semiconductors , 1971 .

[36]  B. S. Naidu,et al.  Physical Properties of Zinc Oxide Films Prepared by dc Reactive Magnetron Sputtering at Different Sputtering Pressures , 2000 .

[37]  K. Boubaker,et al.  Effect of europium content on physical properties of In2O3 thin films for sensitivity and optoelectronic applications , 2016, Bulletin of Materials Science.

[38]  J. Gómez‐Herrero,et al.  WSXM: a software for scanning probe microscopy and a tool for nanotechnology. , 2007, The Review of scientific instruments.