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

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.

2012 ◽  
Vol 485 ◽  
pp. 144-148
Author(s):  
Jian Lin Chen ◽  
Yan Jie Ren ◽  
Jian Chen ◽  
Jian Jun He ◽  
Ding Chen

Preferentially oriented Al-doped ZnO thin films with doping concentration of 1, 2, 3, 5 and 10 mol% respectively were prepared on glass substrates via sol-gel route. The crystallinity of films was characterized by X-ray diffraction and the surface morphologies were observed by scanning electron microscopy. The results show that ZnO:Al films at low doping concentration (1, 2 mol%) grow into dense homogenous microstructure. However, as for high doping concentration (3, 5, 10 mol%), Al3+ precipitate in the form of amorphous Al2O3 and ZnO:Al films exhibit heterogeneous nucleation and exceptional growth of the big plate-like crystals at the interface of the amorphous Al2O3 and ZnO:Al matrix.


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.


Author(s):  
Ali sadek Kadari ◽  
Abdelkader Nebatti Ech-Chergui ◽  
Mohamed walid Mohamedi ◽  
Abdelhalim Zoukel ◽  
Tair Sabrina ◽  
...  

Abstract Pure and Al-doped ZnO thin films were successfully deposited with sol-gel dip coating on both substrates Si (100) and glass. The structural, chemical, morphological and optical properties as a function of the annealing temperature and dopant atomic concentration were investigated by means of X-ray diffraction, Energy dispersive X-ray, Scanning Electron Microscopy, and spectrophotometry. All the pure and doped films show a polycrystalline nature and hexagonal in structure. Accurate doping was proven by EDX. In addition, the SEM analysis revealed that the films possess uniform distribution throughout the surface and the grain dimension decreases with Al doping. From the transmittance measurements, it is see that all films are over 55% in the visible region and the band gap energy increases from 3.28 to 3.45 eV with the increase of Al concentration.


Author(s):  
Selma M.H. AL-Jawad ◽  
Zahraa S. Shakir ◽  
Duha S. Ahmed

ZnO/MWCNTs hybrid and doped with different concentration of Nickel element prepared by using Sol-gel been technique reported. All samples were prepared and characterized by X-Ray Diffraction Analysis (XRD), Energy Dispersive X-ray Spectroscopy (EDS), Fourier-Transform Infrared Spectroscopy (FTIR), Field-Emission Scanning Electron Microscopy (FE-SEM), and UV-Vis spectroscopy have been identified the structural, optical and morphological properties. X-ray diffraction showed the polycrystalline nature with hexagonal wutzite structure of hybrid and doped with Nickel. The crystalline size of the hybrid nanostructure was increasing from 23.73 nm to 34.59 nm. Besides, the UV-Vis spectroscopy showed a significant decrease in the band gap values from 2.97 eV to 2.01 eV. Whereas the FE-SEM analysis confirm the formation spherical shapes of ZnO NPs deposited on cylindrical tubes representing the MWCNTs. The antibacterial activity reveals that the inhibition zone of Ni doped-ZnO/MWCNTs hybrid was 28.5 mm, 26.5 mm toward E. coli and S. aureus bacteria, respectively.


2010 ◽  
Vol 638-642 ◽  
pp. 2915-2920
Author(s):  
Bajirao K. Sonawane ◽  
Mukesh P. Bhole ◽  
Dnyaneshwar S. Patil

Single crystalline a-axis Mg doped ZnO thin films (MgxZn1-xO) were successfully prepared by sol-gel spin coating method using Zinc acetate, Magnesium acetate as precursors with ethanol as a solvent. The prepared solutions were used to deposit the films on silicon (100) substrate for different mole concentrations (x = 0.1 to 0.33). All deposited films were annealed at 450 0C to get dense crystalline films. X-ray Diffractometer (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Analysis by X-ray (EDAX), Fourier Transform Infrared Spectroscopy (FTIR), Ellipsometry and semiconductor characterization system with probe station were used to characterize the deposited films for structural, chemical, optical, mechanical and electrical properties. The intense absorption peak was observed in the IR spectra for all deposited films showing bond position of fundamental ZnO peak for all Mg mole concentrations. From the XRD spectra, it revealed that the deposited films were single crystalline and a-axis oriented. EDAX spectra clearly showed the peak of Mg along with Zn and O indicating the successful incorporation of Mg into the ZnO. The refractive index was successfully tailored from 1.6 to 1.11 corresponding to 0.1 to 0.33 Mg mole concentration. The refractive index was found to be decrease with an increase in Mg mole concentration. I-V characteristics shows decrease in current with increase in the Mg mole concentration. Significant effect was not observed on thickness of deposited films due to the varying Mg mole fraction. Through SEM image, it was noted that the uniform film of Mg doped ZnO was deposited on the silicon substrate. Our results explore the applicability of MgZnO as cladding layer material to form effective and efficient heterostructure with ZnO as an active layer for the optical wave-guide applications.


Author(s):  
Tran Thi Ngoc Anh ◽  
Tran Thi Ha ◽  
Nguyen Viet Tuyen ◽  
Pham Nguyen Hai

This paper presents results of preparation of Ag doped ZnO bulk sample by solid state reaction and Ag doped ZnO thin films by sputtering method. Effect of doping concentration (1, 2 and 4%) on the properties of the thin films was investigated. Various methods were utilized to investigate characteristics of the samples: X-ray diffraction, Raman scattering spectroscopy, photoluminescence, energy dispersive X-Ray spectroscopy, scanning electron microscopy, atomic force microscope, absorption spectroscopy and Hall measurement. The results show that Ag diffused into ZnO crystal lattice after heat treatment at 1200oC. As-prepared thin film samples exhibit low resistivity in the order of 10-3Ω.cm. The film doped with 2% Ag shows the lowest resistivity of 1.8´10-3Ω.cm which is potential for making transparent electrodes in optoelectronics.


2007 ◽  
Vol 124-126 ◽  
pp. 339-342
Author(s):  
Gun Hee Kim ◽  
Hong Seong Kang ◽  
Dong Lim Kim ◽  
Hyun Woo Chang ◽  
Byung Du Ahn ◽  
...  

Cu-doped ZnO (denoted by ZnO:Cu) films have been prepared by pulsed laser deposition using 3 wt. CuO doped ZnO ceramic target. The carrier concentrations (1011~1018 cm-3) and, electrical resistivity (10-1~105 cm) of deposited Cu-doped ZnO thin films were varied depending on deposition conditions. Variations of electrical properties of Cu-doped ZnO indicate that copper dopants may play an important role in determining their electrical properties, compared with undoped films. To investigate effects of copper dopants on the properties of ZnO thin films, X-Ray diffraction (XRD), photoluminescence (PL), and Hall measurements have been performed and corresponded.


2017 ◽  
Vol 35 (1) ◽  
pp. 246-253 ◽  
Author(s):  
◽  
Ziaul Raza Khan ◽  
Anver Aziz ◽  
Mohd. Shahid Khan ◽  
M.U. Khandaker

AbstractZnO thin films were fabricated on quartz substrates at different zinc acetate molar concentrations using sol-gel spin coating method. The samples were characterized using X-ray diffraction, field emission scanning electron microscope, UV-Vis spectroscopy, FT-IR spectroscopy and photoluminescence spectroscopy. Sub-band gap absorption of ZnO thin films in the forbidden energy region was carried out using highly sensitive photothermal deflection spectroscopy (PDS). The absorption coefficients of ZnO thin films increased in the range of 1.5 eV to 3.0 eV, upon increasing zinc concentration. The optical band gaps were evaluated using Tauc’s plots and found to be in the range of 3.31 eV to 3.18 eV. They showed the red shift in the band edge on increase in zinc concentration. The PL spectra of ZnO thin films revealed the characteristic band edge emission centered at the 396 nm along with green emission centered at the 521 nm.


2019 ◽  
Vol 17 (40) ◽  
pp. 95-107
Author(s):  
Selma M. H. Al-Jawad

Pure and Fe-doped zinc oxide nanocrystalline films were preparedvia a sol–gel method using -C for 2 h.The thin films were prepared and characterized by X-ray diffraction(XRD), atomic force microscopy (AFM), field emission scanningelectron microscopy (FE-SEM) and UV- visible spectroscopy. TheXRD results showed that ZnO has hexagonal wurtzite structure andthe Fe ions were well incorporated into the ZnO structure. As the Felevel increased from 2 wt% to 8 wt%, the crystallite size reduced incomparison with the pure ZnO. The transmittance spectra were thenrecorded at wavelengths ranging from 300 nm to 1000 nm. Theoptical band gap energy of spin-coated films also decreased as Fedoping concentration increased. In particular, their optical band gapenergies were 3.75, 3.6, 3.5, 3.45 and 3.3 eV doping concentration of0%, 2%, 4%, 6% and 8% Fe, respectively. The performance of thepure and doped ZnO thin films was examined for the photocatalyticactivity using organic dyes (methyl orange, methyl blue, methylviolet). The samples ZnO with concentration of Fe showed increasedphotocatalytic activity with an optimal maximum performance at0.8 wt%.


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