Influence of Annealing Temperature on ZnO Thin Films Prepared by Single and Multi-step Sol-gel Processes

2006 ◽  
Vol 957 ◽  
Author(s):  
Lee Huat Kelly Koh ◽  
Shane O'Brien ◽  
Pierre Lovera ◽  
Gareth Redmond ◽  
Gabriel M Crean
Keyword(s):  
Thin Films ◽  
Zinc Acetate ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Single Layer ◽  
Single Step ◽  
Zno Thin Films ◽  
Visible Range ◽  
Zno Films ◽  
Axis Orientation

ABSTRACTZnO thin films were prepared on borosilicate glass from both single- and multi- step coating deposition of a sol-gel prepared with anhydrous zinc acetate [Zn(C2H3O2)2], monoethanolamine [H2NC2H4OH ] and isopropanol. ZnO films prepared over a range of zinc acetate concentrations, for a fixed annealing temperature, showed that sol-gels prepared with a 0.3M zinc acetate concentration resulted in the formation of films with the greatest degree of c-axis orientation. In this study, a detailed investigation of the influence of process annealing temperature over the range 450 – 550°C on the microstructural, physical, electronic and optical properties of these single and multi-step ZnO thin films around this 0.3M zinc concentration set point is presented. X-ray analysis showed that all single-step deposition thin films were preferentially orientated along the [002] c-axis direction of the crystal. In contrast, only the multi-layer film annealed at 550°C showed similar preferential orientation. All single step deposited films showed a similar average optical transmittance above 87%, independent of annealing temperature. The transmittance of the multi-step films was shown to be strongly correlated to the degree of c-axis orientation. The optical band-gap energy was evaluated to be 3.298 – 3.316 eV for all samples. The photoluminescence spectra of the single layer ZnO films showed a strong emission centred at ca. 405 nm, which blue shifted with increasing annealing temperature. The multi-layer ZnO samples emitted throughout the UV and the visible range, with the samples prepared at 500 and 550°C showing the expected ZnO emission peak at 380 nm. Despite being thicker, the emission from the multi- layer samples was less than measured for the single layer samples. The effect of sol-gel annealing temperature and deposition process on film microstructure, morphology, electrical resistivity and optical transparency is detailed.

scholarly journals Preparation of Glass Plate-Supported Nanostructure ZnO Thin Film Deposited by Sol-Gel Spin-Coating Technique and Its Photocatalytic Degradation to Monoazo Textile Dye

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
Mohammad Hossein Habibi ◽  
Mohammad Khaledi Sardashti
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Photocatalytic Degradation ◽  
Spin Coating ◽  
Sol Gel ◽  
Glass Plate ◽  
Zno Thin Films ◽  
Visible Range ◽  
Textile Dye ◽  
Axis Orientation

Glass plate-supported nanostructure ZnO thin films were deposited by sol-gel spin coating. Films were preheated at275∘Cfor 10 minutes and annealed at 350, 450, and550∘Cfor 80 minutes. The ZnO thin films were transparent ca 80–90% in visible range and revealed that absorption edges at about 370 nm. Thec-axis orientation improves and the grain size increases which was indicated by an increase in intensity of the (002) peak at34.4∘in XRD corresponding to the hexagonal ZnO crystal. The photocatalytic degradation of X6G an anionic monoazo dye, in aqueous solutions, was investigated and the effects of some operational parameters such as the number of layer and reusability of ZnO nanostructure thin film were examined. The results showed that the five-layer coated glass surfaces have a very high photocatalytic performance.

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.

Effect of Ruthenium Concentration on Structural and I-V Characteristics of ZnO Thin Films by Sol–Gel Method

2017 ◽  
Vol 05 (01) ◽  
pp. 1750004
Author(s):  
R. Vettumperumal ◽  
S. Kalyanaraman ◽  
R. Thangavel
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Zno Thin Films ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Doped Zno

Nanocrystalline ruthenium (Ru)-doped ZnO thin films on sapphire substrate was prepared using sol–gel method by spin coating technique. The structural and I-V characteristics of Ru doped ZnO thin films were studied from the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) analysis and Raman spectroscopy. X-ray diffraction (XRD) results revealed that the deposited films belonged to hexagonal wurtzite structure with c-axis orientation. It is also confirmed from the Raman spectra. Enhancement of longitudinal optical (LO) phonon is observed by the strong electron–phonon interaction. An observed increment in sheet resistance with increase in dopant percentage of Ru (1–2[Formula: see text]mol%) in ZnO films was found and better I-V characteristic behavior was observed at 1[Formula: see text]mol% of Ru-doped ZnO thin films. Trap limited current flow inside the material was calculated from the log I versus log V plot in the higher voltage region.

Optical and Electrical Characteristic of Layer-by-Layer Sol-Gel Spin Coated Nanoparticles ZnO Thin Films

2011 ◽  
Vol 364 ◽  
pp. 149-153 ◽  
Author(s):  
Shafinaz Sobihana Shariffudin ◽  
Farliana Samat Farah ◽  
Sukreen Hana Herman ◽  
Mohamad Rusop
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Reference Sample ◽  
Zno Thin Films ◽  
Visible Range ◽  
Zno Films ◽  
Layer By Layer ◽  
Voltage Measurement ◽  
Vis Spectroscopy ◽  
Reference Samples

Transparent nanoparticles ZnO thin films have been deposited on glass substrates using sol-gel spin coating technique. 0.35M sol were prepared by dissolving zinc acetate dehydrate in 2-methoxyethanol with monoethanolamine as the stabilizer. In this paper, a novel method called layer-by-layer is introduced, where the thin film is not only dried after each layer is spin-coated, but also directly annealed at 500°C to improve the electrical and optical properties of the films. Samples without annealing were also prepared as the reference sample. ZnO thin films were characterized using current-voltage measurement, UV-Vis spectroscopy and photoluminescence spectroscopy. The results revealed that layer-by-layer ZnO thin films have lower resistivity compared to the reference samples with a maximum value of 0.77Ω.cm for ZnO films deposited with 2 layers. Transmittance spectra show that the films were transparent in the visible range above 400nm with range of 86%-98% for the layer-by-layer ZnO films. The optical band gaps were between 3.2 to 3.3eV for both layer-by-layer and the reference samples. PL spectra indicate that layer-by-layer method improves the crystallinity of the films.

Microstructural and Electrical Conductivity of Annealed ZnO Thin Films

2014 ◽  
Vol 970 ◽  
pp. 120-123 ◽  
Author(s):  
Peh Ly Tat ◽  
Karim bin Deraman ◽  
Wan Nurulhuda Wan Shamsuri ◽  
Rosli Hussin ◽  
Zuhairi Ibrahim
Keyword(s):  
Thin Films ◽  
Low Cost ◽  
Sol Gel ◽  
Hexagonal Wurtzite Structure ◽  
Dip Coating ◽  
Zno Thin Films ◽  
Zno Films ◽  
Axis Orientation ◽  
Glass Substrates ◽  
Afm Micrographs

Undoped nanocrystalline ZnO thin films were deposited onto the glass substrates via the low cost sol-gel dip coating method. The as-grown ZnO films were annealed at the temperatures ranging from 400 °C to 550 °C. The X-ray diffraction (XRD) pattern revealed that the annealed ZnO films were polycrystalline with hexagonal wurtzite structure and majority preferentially grow along (002) c-axis orientation. Atomic force microscopy (AFM) micrographs showed the improvement of RMS roughness and grain size as annealing temperature increased. The ZnO films that annealed at 500 oC exhibited the lowest resistivity value.

ANNEALING TREATMENT OF ZnO THIN FILMS DEPOSITED BY SOL–GEL METHOD

2012 ◽  
Vol 19 (05) ◽  
pp. 1250055 ◽  
Author(s):  
M. SALEEM ◽  
L. FANG ◽  
Q. L. HUANG ◽  
D. C. LI ◽  
F. WU ◽  
...  
Keyword(s):  
Thin Films ◽  
Spin Coating ◽  
Annealing Temperature ◽  
Optical Band Gap ◽  
Sol Gel ◽  
Annealing Treatment ◽  
Zno Thin Films ◽  
Axis Orientation ◽  
Transmittance Spectra ◽  
Glass Substrates

Highly transparent ZnO thin films were deposited on glass substrates by using a simple and inexpensive multi-step sol–gel spin coating process. This research investigated the effects of annealing temperature in the range from 350–600°C on the microstructure, surface morphology and optical properties of thin films by using XRD, SEM and transmittance spectra. The XRD results showed that the c-axis orientation of ZnO thin films was improved with the increase of annealing temperature. The grain size increases from 16.6–19.7 nm with the increase in temperature. The transmittance spectra indicated that the transmittance and direct optical band gap Eg of the films showed a decreased trend with annealing temperature. It is found that the tensile stress exist in the films, which decreases with the increase in annealing temperature up to 500°C, on further increasing the annealing temperature up to 600°C, the stress in the film changes from tensile to compressive nature.

Growth and Characterisation of Nanocrystalline ZnO Thin Films by Dip Coating Technique

2013 ◽  
Vol 832 ◽  
pp. 368-373
Author(s):  
Mohd Firdaus Malek ◽  
Mohamad Hafiz Mamat ◽  
Mohd Zainizan Sahdan ◽  
Musa Mohamed Zaihidi ◽  
Zuraida Khusaimi ◽  
...  
Keyword(s):  
Thin Films ◽  
Zinc Acetate ◽  
Sol Gel ◽  
Homogeneous Solution ◽  
Nir Spectroscopy ◽  
Dip Coating ◽  
Zno Thin Films ◽  
Molar Ratio ◽  
Zno Films ◽  
Glass Substrates

Nanocrystalline zinc oxide (ZnO) thin films have been obtained by the sol gel process. A stable and homogeneous solution was prepared by dissolving zinc acetate dehydrate as a starting material in a solution of 2-methoxyethanol and monoethanolamine (MEA). The molar concentration of zinc acetate was fixed at 0.6 mol/L while the molar ratio of MEA to zinc acetate was kept at 1:1. The films were deposited by various deposition speeds by dip-coating on glass substrates, and subsequently transformed into nanocrystalline pure ZnO films after a thermal treatment. Various deposition speeds were selected as the parameter to optimize the thin films quality. The structural and optical properties of the ZnO films were studied by X-ray diffraction (XRD), UV-Vis-NIR spectroscopy, respectively. The electrical properties of the ZnO thin films were characterised by dc 2 probing system and power supply (Advantest R6243). It was found that the deposition speed affects the resultant properties of ZnO thin films.

Annealing Temperature Dependence of Optical Properties of Sol-Gel ZnO Thin Films with Different Sol Aging Time

2017 ◽  
Vol 48 ◽  
pp. 211-217 ◽  
Author(s):  
Ji Tao Li ◽  
Ding Yu Yang ◽  
Xing Hua Zhu
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Aging Time ◽  
Annealing Temperature ◽  
Urbach Energy ◽  
Energy Gap ◽  
Sol Gel ◽  
Zno Thin Films ◽  
Zno Films ◽  
Ultraviolet Emission

ZnO thin films on glass substrates have been successfully fabricated by sol-gel method for various aging time and annealing temperature. X-ray diffraction (XRD) patterns showed the crystallites at (100), (002) and (101) plane of hexagonal wurtzite structure. Atomic force microscope (AFM) images were used to investigate the surface morphology. The transmittance, energy gap, Urbach energy and photoluminescence (PL) of samples were investigated to explore the effects of annealing temperature on optical properties of ZnO thin films under different sol aging time. The transmittance spectra of thin films aged for 24 hours and 48 hours revealed the enhanced transmittance in visible region as rising annealing temperature, also, the optical band gap of the samples increased and Urbach energy decreased. The photoluminescence (PL) spectra of samples aged for 24 hours and 48 hours were studied and found the increased ultraviolet emission at ~387 nm, and various decreased visible emissions with rising annealing temperature. Nevertheless, the excessive sol aging time for 72 hours deteriorated the optical characteristics of thin films, resulting in that transmittance, energy gap and ultraviolet emission declined, and visible emissions increased with rising annealing temperature. The optical performances of the ZnO films aged for different time have no the same dependence of annealing temperature.

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.

Investigation on the Structural and Optical Properties of ZnO Thin Films Prepared by Sol-Gel Method

2014 ◽  
Vol 971-973 ◽  
pp. 89-92
Author(s):  
Zong Hu Xiao ◽  
Yong Ping Luo ◽  
Shun Jian Xu ◽  
Wei Zhong ◽  
Hui Ou ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Band Gap ◽  
Emission Band ◽  
Sol Gel ◽  
Layer Growth ◽  
Zno Thin Films ◽  
Visible Range ◽  
Island Growth ◽  
Axis Orientation

Zinc oxide (ZnO) thin films were prepared by sol-gel spin coating technique, which were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), NKD thin film analysis system and fluorescence spectrophotometer. The results show that ZnO thin films with the each layer thickness of 80 nm present obvious c-axis orientation. With the increase of coating layers, the c-axis orientation characteristic weakens. The reason is considered that the growth mode of ZnO thin films transforms from layer growth to island growth. For the ZnO thin film with 4 layers, it has a compact surface and a uniform particle size of approximately 50 nm, and the photoluminescence (PL) spectrum primarily consists of two PL emission bands, one is a strong and narrow ultraviolet (UV) emission band, another is a weak and broad luminescence emission band from 400 nm to 650 nm. The average transmittance in the visible range is beyond 90%. A optical band gap of 3.26 eV, slightly less than the intrinsic band gap width of 3.37 eV, is obtained by Tauc plotting method. The defects, such as Zn or O vacancies, grain boundaries, are considered to be the main factors causing this situation.

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