scholarly journals EPR Spectroscopy of Different Sol Concentration Synthesized Nanocrystalline-ZnO Thin Films

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Manju Arora ◽  
Rayees A. Zargar ◽  
S. D. Khan

Nanocrystalline zinc oxide (nc-ZnO) thin films were grown on p-type silicon substrate through spin coating by sol-gel process using different sol concentrations (10 wt.%, 15 wt.%, and 25 wt.%). These films were characterized by high resolution nondestructive X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDS) attachment, and electron paramagnetic resonance (EPR) techniques to understand variations in structural, morphological, and oxygen vacancy with respect to sol concentration. The film surface morphology changes from nanowall to nanorods on increasing sol concentration. EPR spectra revealed the systematic variation from ferromagnetic to paramagnetic nature in these nc-ZnO films. The broad EPR resonance signal arising from the strong dipolar-dipolar interactions among impurity defects present in nc-ZnO film deposited from 10 wt.% sol has been observed and a single strong narrow resonance signal pertaining to oxygen vacancies is obtained in 25 wt.% sol derived nc-ZnO film. The concentrations of impurity defects and oxygen vacancies are evaluated from EPR spectra, necessary for efficient optoelectronic devices development.

2006 ◽  
Vol 510-511 ◽  
pp. 670-673 ◽  
Author(s):  
Chong Mu Lee ◽  
Yeon Kyu Park ◽  
Anna Park ◽  
Choong Mo Kim

This paper investigated the effects of annealing atmosphere on the carrier concentration, carrier mobility, electrical resistivity, and PL characteristics as well as the crystallinity of ZnO films deposited on sapphire substrates by atomic layer deposition (ALD). X-ray diffraction (XRD) and photoluminescence (PL) analyses, and Hall measurement were performed to investigate the crystallinity, optical properties and electrical properties of the ZnO thin films, respectively. According to the XRD analysis results, the crystallinity of the ZnO film annealed in an oxygen atmosphere is better than that of the ZnO film annealed in a nitrogen atmosphere. It was found that annealing undoped ZnO films grown by ALD at a high temperature above 600°C improves the crystallinity and enhances UV emission.


2013 ◽  
Vol 669 ◽  
pp. 181-184
Author(s):  
Nan Ding ◽  
Li Ming Xu ◽  
Bao Jia Wu ◽  
Guang Rui Gu

Zinc oxide (ZnO) films were prepared on Si substrates and then aluminum nitride (AlN) films were deposited on ZnO films by radio frequency (RF) magnetron sputtering. The crystal orientation, crystallite structure and surface morphology of AlN/ZnO films were characterized by X-ray diffraction (XRD), Raman spectrum and scanning electron microscopy (SEM). It was indicated that the AlN films were closely deposited on the ZnO film and had good crystallinity. Moreover, about 1μm-sized crystal particles with high c-axial orientation distributed uniformly on the AlN/ZnO film surface. It was indicated that ZnO could be a promising candidate as buffer layer for preparation of AlN thin films.


2015 ◽  
Vol 1107 ◽  
pp. 678-683 ◽  
Author(s):  
Lam Mui Li ◽  
Azmizam Manie Mani ◽  
Saafie Salleh ◽  
Afishah Alias

Zinc Oxide (ZnO) has attracted much attention because of its high optical transmittance approximately ~80 % with a wide band gap of (3.3 eV at 300 K) and a relatively low cost material. ZnO thin films were deposited on plastic substrate using RF powered magnetron sputtering method. The target used is ZnO disk with 99.99 % purity. The sputtering processes are carried out with argon gas that flow from 10-15 sccm. Argon is used to sputter the ZnO target because the ability of argon that can remove ZnO layer effectively by sputtering with argon plasma bombardment. The deposited ZnO thin films are characterized using X-Ray Diffraction (XRD) and UV-Vis Spectrometer. The analysis of X-ray diffraction show that good crystalline quality occurs at nominal thickness of 400 nm. The optical studies showed that all the thin films have high average transmittance of approximately 80 % and the estimated value of optical band gap is within 3.1 eV-3.3 eV range.


2011 ◽  
Vol 287-290 ◽  
pp. 2347-2350
Author(s):  
Rong Fan ◽  
Lin Jun Wang ◽  
Jian Huang ◽  
Ke Tang ◽  
Ji Jun Zhang ◽  
...  

ZnO thin films were deposited by radio frequency (R. F.) magnetron sputtering on various diamond film substrates with different surface roughness. The influence of surface roughness on structural properties and surface morphology of ZnO thin films was investigated by X-ray diffraction (XRD) and atom force microscopy (AFM), respectively. Only on the nanocrystalline and free-standing diamond substrates, ZnO films with preferential c-axis orientation and smooth surface were obtained.


2021 ◽  
Vol 21 (3) ◽  
pp. 1560-1569
Author(s):  
K. Moorthy ◽  
S. S. R. Inbanathan ◽  
C. Gopinathan ◽  
N. P. Lalla ◽  
Abdulaziz Ali Alghamdi ◽  
...  

Root like structured Ni-doped zinc oxide [Zn(1-x)NixO (x = 0.09)] thin films were deposited on a non-conducting glass substrate by indigenously developed spray pyrolysis system at optimized substrate hotness of 573±5 K. Thus obtained Ni-doped ZnO thin films were characterized by UV-visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Atomic Force Microscopy (AFM). XRD result revealed that Ni-doped ZnO has a polycrystalline nature with a hexagonal wurtzite structure. For pure ZnO and Ni-doped ZnO thin films, the particle sizes were 60.9 and 53.3 nm while lattice strain values were 1.56×10−3 and 1.14×10−3, respectively. The film surface showed characteristic root-like structure as observed by the SEM. It was observed that the Ni-doped ZnO thin films were grown in high density along with more extent of branching as compared to pure ZnO thin films but retained the root-like morphologies, however, the branches were more-thinner and of shorter lengths. AFM analysis showed that the surface grains of the Ni-doped samples are homogeneous with less RMS roughness values compared with the undoped ZnO samples. The photocatalytic activity of the prepared thin films was evaluated by the degradation of methyl orange (MO) dye under UV light irradiation. Pure ZnO and Ni-doped ZnO thin films took 150 min and 100 min to degrade about 60% MO dye, respectively.


2019 ◽  
Vol 17 (12) ◽  
pp. 987-990
Author(s):  
K. Rathi Devi ◽  
G. Selvan ◽  
M. Karunakaran ◽  
G. Rajesh Kanna ◽  
K. Kasirajan

In this work, Mn doped Zinc Oxide (ZnO) thin films were coated onto glass substrates by low cost SILAR technique by altering dipping cycle such as 40, 60, 80 and 100. The film thickness was estimated using weight gain method and it revealed that the film thickness increased with dipping cycle. The structural, morphological, elemental and FTIR properties of the coated Mn doped ZnO films were studied using X-ray diffraction (XRD), scanning electron microscope (SEM), EDAX and FTIR spectrophotometer respectively. The prepared films were found to be hexagonal structure with polycrystalline in nature with preferential orientation along (002) plane. X-ray line profile analysis was used to evaluate the micro structural parameters. The crystallite size values are increased with increase of dipping cycle. Morphological results showed that the dipping cycle has a marked effect on morphology of the prepared Mn doped ZnO thin films. EDAX studies showed that the presence of Zinc, Oxygen and Mn content.


2013 ◽  
Vol 538 ◽  
pp. 30-33 ◽  
Author(s):  
Lan Li Chen ◽  
Zhong Ke Tang ◽  
Ming Ji Shi

ZnO films covered with microrods were grown on silicon and porous silicon through electrochemical deposition with silicon or porous silicon as cathode, a platinum wire as anode, and zinc chloride solution of 0.05mol/L as electrolyte. The morphologies by SEM and the crystal structures by XRD were studied. The photoluminescence spectra were also measured. And the mechanisms of the growth and the photoluminescence of the ZnO thin films were analyzed and compared. Studies showed that the luminous intensity of ZnO thin films is different under different conditions, but its peak is located between 370-385nm, luminous intensity of the ZnO film deposited on porous silicon and then annealed is weaker.


2017 ◽  
Vol 05 (01) ◽  
pp. 1750004
Author(s):  
R. Vettumperumal ◽  
S. Kalyanaraman ◽  
R. Thangavel

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.


2015 ◽  
Vol 1132 ◽  
pp. 217-223
Author(s):  
E.R. Rwenyagila ◽  
B. Agyei-Tuffour ◽  
M.G.Z. Kana ◽  
O. Akin-Ojo ◽  
W.O. Soboyejo

This work examines the modification of the structural and optical properties of ZnO thin films by control of deposition and post-treatment parameters. ZnO thin films were deposited by RF magnetron sputtering from a ceramic target locally made at SHESTCO in Abuja, Nigeria. X-ray diffraction measurements characterized the different films prior to thermal annealing as extremely amorphous with average UV-VIS transmittance spectra between 80 and 90%. Annealing at different temperatures and time spans influenced the formation of Wurtzite (002) oriented ZnO crystallites. Contrary to the crystallinity of the films, which was strongly influenced by the deposition power, the optical transmission of the films was only slightly influenced by the deposition power and it was less sensitive to the crystallinity of ZnO thin films.


2003 ◽  
Vol 769 ◽  
Author(s):  
Yang-Ming Lu ◽  
Shu-I Tsai ◽  
Chen-Min Chang

AbstractThe properties of ZnO thin film are currently of great commercial and scientific interest due to its particular properties such as highly conductive, transparent as well as chemical stability and nontoxic. The Ti doping ZnO thin films were deposited by simultaneously magnetron co-sputtering from both Zn and Ti targets in a mixture of oxygen and argon gases onto heated Corning 7059 glass substrates in this study. The experimental results show that deposition rate of ZnO films are strongly dependent on DC power of Ti target. The growth rate initially increases and changes to decrease when the DC power of Ti target further rises. The content of Ti in the ZnO films increases with the applied DC power of Ti target. The lattice constant of ZnO (002) increases with DC power of Ti target due to incorporated Ti into the lattice of ZnO. The crystalline size becomes smaller when the DC power of Ti target was raised. The visible transmittance is a little lowered when slight Ti incorporated but still average maintains above 80%. The lowest resistivity of undoped ZnO film obtained in this study is 4.14×10-3 ohm-cm and further decreased to 1.02×10-3 ohm-cm after being doped a trace of Ti.


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