Synthesis, Characterization and Hall Effect Measurements of Nanocrystalline ZnO Thin Films

2012 ◽  
Vol 510-511 ◽  
pp. 186-193 ◽  
Author(s):  
Ashari Maqsood ◽  
M. Islam ◽  
M. Ikram ◽  
S. Salam ◽  
S. Ameer
Keyword(s):  
Thin Films ◽  
Hall Effect ◽  
Sol Gel ◽  
Visible Region ◽  
Zno Thin Films ◽  
Zno Films ◽  
Morphological Studies ◽  
Hall Effect Measurements ◽  
Scherrer Formula

ZnO thin films were prepared by sol-gel method. Prepared thin films were then characterized by SEM, XRD, EDX and Hall effect measurements. SEM confirmed the morphological studies of ZnO thin films. Crystallite size is calculated using the Scherrer formula. Crystallite and grain sizes are obtained through XRD and SEM. EDS analysis confirms mass percentage of ZnO deposited. Decreasing trend of magneto resistance with temperature is observed. The optical transmission spectra of the solgel deposited ZnO thin films showed high transmittance (>70%) in the visible region and indicates that the transmittance of ZnO films gradually decreased as the thickness increased. Decreasing trend of resistivity and sheet resistance with thickness are also observed. The IV characterization of ZnO thin films under influence of UV and dark conditions are reported. The dc electrical resistivity data follow the hoping model.

scholarly journals Magnetic and Electrical Properties of Undoped and Holmium Doped ZnO Thin Films Grown by Sol-Gel Method

2013 ◽  
Vol 8-9 ◽  
pp. 301-308 ◽  
Author(s):  
Mihaela Popa ◽  
Guy Schmerber ◽  
Dana Toloman ◽  
Mihai S. Gabor ◽  
Amalia Mesaros ◽  
...  
Keyword(s):  
Thin Films ◽  
Hall Effect ◽  
Quantum Interference ◽  
Sol Gel ◽  
Zno Thin Films ◽  
Zno Films ◽  
Gel Method ◽  
Sol Gel Method ◽  
Hall Effect Measurements ◽  
Doped Zno

Undoped and holmium-doped ZnO thin films were obtained, using the sol-gel method. The films were characterized by scanning electron microscopy (SEM), Hall effect measurements, electron paramagnetic resonance (EPR) spectroscopy and superconducting quantum interference device vibrating sample magnetometry (SQUID-VSM). The Hall effect measurements have indicated a n-type conduction with a resistivity of about 3.2 Ω.cm for the undoped ZnO and of about 4.5 Ω.cm for the 5 at. % Ho-doped ZnO thin films. The EPR measurements have indicated the presence of interstitial zinc in the undoped ZnO and the presence of zinc vacancies in 5 at. % Ho-doped ZnO. Ho (5 at. %)-doped ZnO films exhibit superparamagnetism at 5 K, while a low paramagnetic behavior was observed at room temperature.

EFFECTS OF Ge DOPING THROUGH ION IMPLANTATION ON THE STRUCTURAL AND OPTICAL PROPERTIES OF ZnO THIN FILMS PREPARED BY SOL-GEL TECHNIQUE

2007 ◽  
Vol 21 (31) ◽  
pp. 5257-5263 ◽  
Author(s):  
S. W. XUE ◽  
X. T. ZU ◽  
X. XIANG ◽  
M. Y. CHEN ◽  
W. G. ZHENG
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Ion Implantation ◽  
Deep Level ◽  
Sol Gel ◽  
Visible Region ◽  
Zno Thin Films ◽  
Zno Films ◽  
Near Band Edge ◽  
Structural And Optical Properties

ZnO thin films were first prepared by the sol–gel process, and then Ge ions were implanted into the ZnO films. The effects of ion implantation on the structural and optical properties of the ZnO films were investigated by X-ray diffraction, photoluminescence (PL), and optical transmittance measurements. Measurement results showed that the intensity of the (002) diffraction peak was decreased and the full width at half maximum was narrowed. PL emission was greatly extinguished after Ge ion implantation. Both the near band edge (NBE) excitonic UV emission at 391 nm and the defect related deep level emission centered at 470 nm in the visible region were decreased after Ge ion implantation. NBE peak and the absorption edge were observed to have a blueshift toward higher energy.

Ultraviolet Sensing by Al-Doped ZnO Thin Films

2011 ◽  
Vol 364 ◽  
pp. 154-158
Author(s):  
Affa Rozana Abdul Rashid ◽  
P. Susthitha Menon ◽  
N. Arsad ◽  
S. Shaari
Keyword(s):  
Thin Films ◽  
Recovery Time ◽  
Annealing Temperature ◽  
Uv Light ◽  
Sol Gel ◽  
Zno Thin Films ◽  
Zno Films ◽  
Doped Zno ◽  
Fabrication And Characterization

We report the fabrication and characterization of an ultraviolet photoconductive sensing by using Al-doped ZnO films. Undoped ZnO, 1 at.% and 2 at% of Al were prepared on quartz glass by sol gel method with annealing temperature of 500°C for 1 hour. The presence of spherical shaped nanoparticles were detected for undoped ZnO by using FESEM. The absorption edge shifted to a lower wavelength by doping with Al and excitonic peak can be observed. The band gap values increased by adding Al. I-V curves reveal an ohmic line and improvement in electrical conductivity when the samples are illuminated by ultraviolet (UV) light with a wavelength of 365 nm. At 1 at.% of Al, the film have a larger increment in photocurrent response when illuminated with UV light compared to undoped ZnO and 2 at.% Al. The thin films have a longer recovery time than response time.

scholarly journals Preparation and Characterization of Indium and Gallium doped Transparent ZnO Films for Solar Cell Applications

2018 ◽  
Vol 34 (5) ◽  
pp. 2325-2331
Author(s):  
Reuben Seth Richter ◽  
A. Yaya ◽  
D. Dodoo-Arhin ◽  
B. Agyei-Tuffour ◽  
Robinson Juma Musembi ◽  
...  
Keyword(s):  
Thin Films ◽  
Zno Thin Films ◽  
Zno Films ◽  
Optical And Electrical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Substrates ◽  
Spray Pyrolysis Deposition ◽  
Hall Effect Measurements

In this work, the effect of indium (In) and gallium (Ga) dopants on the structural, optical and electrical properties of ZnO thin films was studied. ZnO thin films were deposited on glass substrates at 400°C using the spray pyrolysis deposition technique. X-ray diffraction (XRD) results indicated that both undoped and doped ZnO films had (002) preferred orientation. The undoped ZnO films were found to exhibit high transmittance above 80%, while indium-doped (In:ZnO) and gallium-doped (Ga:ZnO) films had transmittance above 60% and 70% respectively. From the Hall Effect measurements, doping improved the conductivity of the ZnO thin films however, In:ZnO films showed higher electrical conductivity compared to Ga:ZnO films. Electron probe microanalysis (EPMA) results were used to confirm the presence of the respective dopants in the thin film samples.

The Preparation and Optical Property of ZnO Thin-Film by Electrospray

2009 ◽  
Vol 155 ◽  
pp. 151-154 ◽  
Author(s):  
Yan Huai Ding ◽  
Ping Zhang ◽  
Yong Jiang ◽  
Fu Xu ◽  
Jing Chen ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Property ◽  
Sol Gel ◽  
Visible Region ◽  
Optical Transmittance ◽  
Zno Thin Films ◽  
Zno Films ◽  
Ultraviolet Region ◽  
Force Microscopy ◽  
Glass Substrates

ZnO thin-films were prepared from sol-gel precursors using electrospray method. The structure, morphology and optical property of ZnO thin-films deposited on glass substrates were investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and absorption spectrums (ABS). The surface images obtained directly from AFM showed the compact ZnO films were composed of wurtzite ZnO nanoparticles. The ZnO films presented high optical transmittance in the visible region and strong absorption in ultraviolet region.

Effects of Withdrawal Speeds on Properties of ZnO Thin Films Prepared by Sol-Gel Immerse Technique

2016 ◽  
Vol 680 ◽  
pp. 124-128 ◽  
Author(s):  
Chao Du ◽  
Yu Chun Zou ◽  
Zhi Qing Chen ◽  
Wen Kui Li ◽  
Shan Shan Luo
Keyword(s):  
Thin Films ◽  
Growth Process ◽  
Sol Gel ◽  
Wavelength Region ◽  
Zno Thin Films ◽  
Zno Films ◽  
Photoelectric Device ◽  
Near Ir ◽  
Crystal Film ◽  
Diffraction Peaks

ZnO thin films have attractive applications in photoelectric device, due to their excellent chemical, electrical and optical properties. In this paper, ZnO thin films with good c-axis preferred orientation and high transmittance are prepared on glass sheets by sol-gel immerse technique. The effects of withdrawal speeds on the growth process of thin film crystal, film crystal orientation and the crystallinity, the optical performance were investigated by XRD, SEM and UV-Vis spectrophotometry. The results show that the thin films were composed of better hexagonal wurtzite crystals with the c-axis prepared orientation. The transmittance of prepared thin films is over 80% in the visible-near IR region from 600 nm - 800 nm. ZnO films have sharp and narrow diffraction peaks, which indicates that the materials exhibit high crystallinity. With the withdrawal speeds increasing, the grain size of ZnO thin films and the intensity for all diffraction peaks were increased gradually. The growth model is changed from the stratified structure into the island structure in the growth process. The transmittance of the thin films decrease in the visible wavelength region, with the withdrawal speeds increasing.

Photocatalytic Properties of ZnO and Ag Doped ZnO Thin Films

2014 ◽  
Vol 685 ◽  
pp. 3-6
Author(s):  
Ying Lian Wang ◽  
Jun Yao Ye
Keyword(s):  
Thin Films ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Structural Features ◽  
Photocatalytic Properties ◽  
Zno Thin Films ◽  
Molar Ratio ◽  
Zno Films ◽  
Doped Zno ◽  
Excellent Adhesion

Pure ZnO thin films and Ag doped ZnO thin films were prepared on quartz substrates by sol-gel process. Structural features and UV absorption spectrum have been studied by XRD and UV-Vis-Nir scanning spectrophotometer. Taking phenol as pollutants, further study of the effect of different annealing temperature and Ag dopant amount of ZnO films on photocatalytic properties was carried out. The results showed that, the optimal annealing temperature on photocatalytic degradation of phenol in this experiment was 300 °C, the best molar ratio of ZnO and Ag was 30:1, which was better than pure ZnO film greatly. Excellent adhesion, recyclable and efficient degradation Ag doped ZnO thin films were found in this experiment.

Structural and Optical Studies of Molarity Based ZnO Thin Films

2017 ◽  
Vol 17 ◽  
pp. 140-148 ◽  
Author(s):  
A. Jacquiline Regina Mary ◽  
S. Arumugam
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Visible Region ◽  
Precursor Solution ◽  
Hexagonal Wurtzite Structure ◽  
Solution Concentration ◽  
Molar Concentration ◽  
Zno Thin Films ◽  
Zno Films ◽  
Average Grain Size

Zinc Oxide thin films were prepared for different precursor solution molarities from 0.025M to 0.1M by spray pyrolysis deposition technique. A comprehensive study was carried out to realize the effect of concentration of precursor on ZnO thin films. The optimized temperature of the glass substrate was 300°C. From the XRD data it is inferred that the films are polycrystalline and hexagonal wurtzite structure . The degree of preferred orientation were along diffraction planes (100), (002) and (101) for all the ZnO films. The intensity of the diffraction peak prepared with 0.1M concentration is higher than those prepared at lower concentrations. The grain size (D) was calculated using Debye-Scherrer formula. It was found that the average grain size increases, when the molar concentration increases. As the solution concentration increases, the band gap decreases. The films are transparent in the visible region (85%), and the transmittance decreases as the molar concentration increases, which is caused by optical scattering at grain boundaries.

scholarly journals Growth of Zn1−x CdxO nanocrystalline thin films by sol-gel method and their characterization for optoelectronic applications

2014 ◽  
Vol 32 (4) ◽  
pp. 688-695 ◽  
Author(s):  
Munirah Munirah ◽  
Ziaul Khan ◽  
Mohd. Khan ◽  
Anver Aziz
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Visible Region ◽  
Zno Thin Films ◽  
Band Edge Emission ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cd Doping ◽  
Vis Spectroscopy ◽  
Doped Zno

AbstractThis paper describes the growth of Cd doped ZnO thin films on a glass substrate via sol-gel spin coating technique. The effect of Cd doping on ZnO thin films was investigated using X-ray diffraction (XRD), UV-Vis spectroscopy, photoluminescence spectroscopy, I–V characteristics and field emission scanning electron microscopy (FESEM). X-ray diffraction patterns showed that the films have preferred orientation along (002) plane with hexagonal wurtzite structure. The average crystallite sizes decreased from 24 nm to 9 nm, upon increasing of Cd doping. The films transmittance was found to be very high (92 to 95 %) in the visible region of solar spectrum. The optical band gap of ZnO and Cd doped ZnO thin films was calculated using the transmittance spectra and was found to be in the range of 3.30 to 2.77 eV. On increasing Cd concentration in ZnO binary system, the absorption edge of the films showed the red shifting. Photoluminescence spectra of the films showed the characteristic band edge emission centred over 377 to 448 nm. Electrical characterization revealed that the films had semiconducting and light sensitive behaviour.

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