ELECTRICAL AND OPTICAL PROPERTIES OF MULTILAYER SOL GEL ZnO COATINGS

2006 ◽  
Vol 20 (23) ◽  
pp. 3357-3364 ◽  
Author(s):  
TALAAT MOUSSA HAMMAD

Multilayer transparent conducting zinc oxide films have been prepared on boro-silicate substrates by the commercially sol gel dip coating process. Each layer was fired at 550°C in a conventional furnace for 15 min. The final coatings were then tempered under a flux of forming gas ( N 2/ H 2) at 400°C for 2 h. The coatings were characterized by surface stylus profiling and optical spectroscopy (UV-NIR). Results show that (1) ZnO films with electrical resistivity of 6×10-4 Ω· cm , free carrier mobility of approximately 77 cm 2/ V · s and free carrier density of approximately 6.14×1019 cm -3 are obtained for multilayers 310 nm and (2) the transmittance is approximately 60.4% and the reflectance is nearly 34.7% are obtained at a wavelength of 800 nm when the thickness of the ZnO multilayers is 310 nm. The crystal structure and grain orientation of ZnO films were determined by X-ray diffraction. SEM investigations revealed that the surface morphology of growing ZnO films on boro-silicate substrate is dominated by the smooth surface with a fine microstructure.

2020 ◽  
Vol 978 ◽  
pp. 384-389
Author(s):  
Sritama Roy ◽  
Saswati Soumya Dash ◽  
Prasanna Kumar Sahu ◽  
Smita Mishra ◽  
Jyoti Prakash Kar

Zinc Oxide (ZnO) thin films were produced by the sol gel dip coating process on the p-type silicon substrate with various withdrawal speeds changing from 1 to 4 cm/min, respectively. The films were annealed at a temperature of 500 °C for an hour in air ambient. The thin film thickness was found to be raised with the rise in withdrawal speed. The uniform distribution of the grains was appeared for all the films. The evolution of c-axis oriented (002) peak was revealed from X-ray diffraction (XRD) studies. The microstructural and optical properties of ZnO films were investigated by Raman, FTIR and photoluminescence spectroscopy (PL). The resistive switching properties of ZnO based memristors were studied by performing the current-voltage (I-V) measurements, where the thin films coated with lower withdrawal speed, have shown better switching property with rapid rise and fall of current during SET and RESET process, respectively.


2016 ◽  
Vol 1133 ◽  
pp. 424-428 ◽  
Author(s):  
Norhidayah Che Ani ◽  
Mohd Zainizan Sahdan ◽  
Nayan Nafarizal ◽  
Siti Nooraya Mohd Tawil

Thin films of undoped and gadolinium-doped zinc oxide (Gd-doped ZnO) with different Gd concentration (1-8 at. %) were deposited onto a glass substrate by sol–gel spin-coating technique. X-ray diffraction (XRD, Bruker D8 Advance) studies confirmed the nature of the films as polycrystalline, with typical hexagonal wurtzite structure. The film also showed variation in crystallite size and change in relative intensities, upon different Gd concentrations. Besides, the influence of Gd concentration on the optical transmittance of ZnO films was studied using ultraviolet-visible spectrophotometer (UV-Vis, Shimadzu UV 1800) in the wavelength range 300-800 nm. The optical transmittance of all films is higher than ~95% in the visible region, and doped films become more transparent. The electrical resistance was measured by two point probe (Keithley-2400). The resistance decrease with increasing Gd concentration up to 2 at.% and it increased for further increase Gd concentrations.


Author(s):  
T. A. Emma ◽  
M. P. Singh

Optical quality zinc oxide films have been characterized using reflection electron diffraction (RED), replication electron microscopy (REM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Significant microstructural differences were observed between rf sputtered films and planar magnetron rf sputtered films. Piezoelectric materials have been attractive for applications to integrated optics since they provide an active medium for signal processing. Among the desirable physical characteristics of sputtered ZnO films used for this and related applications are a highly preferred crystallographic texture and relatively smooth surfaces. It has been found that these characteristics are very sensitive to the type and condition of the substrate and to the several sputtering parameters: target, rf power, gas composition and substrate temperature.


2001 ◽  
Vol 692 ◽  
Author(s):  
K. S. Huh ◽  
D. K. Hwang ◽  
K. H. Bang ◽  
M. K. Hong ◽  
D. H. Lee ◽  
...  

AbstractA series of ZnO thin films with various deposition temperatures were prepared on (100) GaAs substrates by radio-frequency magnetron sputtering using ZnO target. The ZnO films were studied by field emission scanning electron microscope(FESEM), x-ray diffraction(XRD), photoluminescence(PL), cathodoluminescence(CL), and Hall measurements. The structural, optical, and electrical properties of the films were discussed as a function of the deposition temperature. With increasing temperature, the compressive stress in the films was released and their crystalline and optical properties were improved. From the depth profile of As measured by secondary ion mass spectrometry(SIMS), As doping was confirmed, and, in order to activate As dopant atoms, post-annealing treatment was performed. After annealing treatment, electrical and optical properties of the films were changed.


2009 ◽  
Vol 24 (8) ◽  
pp. 2541-2546 ◽  
Author(s):  
Eisuke Yokoyama ◽  
Hironobu Sakata ◽  
Moriaki Wakaki

ZrO2 thin films containing silver nanoparticles were prepared using the sol-gel method with Ag to Zr molar ratios [Ag]/[Zr] = 0.11, 0.25, 0.43, 0.67, 1.00, 1.50, and 2.33. After dip coating on glass substrate, coated films were annealed at 200 and 300 °C in air. X-ray diffraction peaks corresponding to crystalline Ag were observed, but a specific peak corresponding to ZrO2 was not observed. At the molar ratio [Ag]/[Zr] = 0.25, the particle size of Ag distributed broadly centered at 17 nm for an annealing temperature of 200 °C and at 25 nm for 300 °C. The films annealed in air at 200 °C showed an absorption band centered at 450 nm because of the silver surface plasmon resonance, whereas films heated at 300 °C in air caused a red shift of the absorption to 500 nm. The absorption peak was analyzed using the effective dielectric function of Ag-ZrO2 composite films modeled with the Maxwell-Garnett expression.


2019 ◽  
Vol 25 (4) ◽  
pp. 365-368
Author(s):  
Pranas USINSKAS ◽  
Živilė STANKEVIČIŪTĖ ◽  
Gediminas NIAURA ◽  
Justinas ČEPONKUS ◽  
Aivaras KAREIVA

In this study we demonstrate, that sol–gel route is suitable to quicker obtain calcium hydroxyapatite (Ca10(PO4)6(OH)2, CHAp) coatings on crystalline Si substrate by modified dip-coating technique. The substrate was dip-coated by precursor and dried for 10 minutes at 200 °C with following cooling using the heating block for 110 min and annealing at 650 °C. Ethylendiamintetraacetic acid and 1,2-ethandiol, and triethanolamine and polyvinyl alcohol were used as complexing agents and as gel network forming agents, respectively. The obtained coatings were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), FTIR spectroscopy and contact angle measurements (CAM).


2014 ◽  
Vol 903 ◽  
pp. 73-77
Author(s):  
Peh Ly Tat ◽  
Karim bin Deraman ◽  
Rosli Hussin ◽  
Wan Nurulhuda Wan Shamsuri ◽  
Zuhairi Ibrahim

ZnO thin films were deposited on the glass substrates via the sol-gel dip coating method. The films were annealed at various temperatures ranging from 350 °C to 550 °C. X-ray diffraction (XRD), and atomic force microscopy (AFM) were used to investigate the effect of annealing temperature on the structural and morphology properties of the films. The as grown films exhibited amorphous pattern while annealed films were polycrystalline structure with (002) preferential growth along c-axis orientation. The AFM micrographs revealed that the RMS roughness of the films increased as the annealing temperature increased. The grain size was ranging from 32.1 nm to 176.0 nm as the annealing temperature increased from 350 °C to 450 °C and decreased to 56.1 nm for 550 °C.


1994 ◽  
Vol 9 (8) ◽  
pp. 2133-2137 ◽  
Author(s):  
Hideki Yoshioka

Thin films in the system (1 - x) PbTiO3−xLa2/3TiO3 were prepared by the sol-gel and dip-coating methods. Phases deposited in the films and the lattice parameters as a function of the composition were investigated by the x-ray diffraction method. The solid solutions with a perovskite structure were formed as a single phase with x up to 0.9. For the composition of x = 1.0, metastable La-Ti-O perovskite phase with a small amount of the impurity phase, La2Ti2O7, was obtained. Simulation of x-ray diffraction patterns based on the defect structure model shows that the structure of the La-Ti-O perovskite phase includes randomly distributed cation vacancies at the A-site, namely (La2/3□1/3)TiO3.


2014 ◽  
Vol 9 (5) ◽  
pp. 618-623 ◽  
Author(s):  
Gonca Ilgu ◽  
Yasemin Caglar ◽  
Saliha Ilican ◽  
Mujdat Caglar ◽  
Serif Ruzgar

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