scholarly journals Passivation Effect on ZnO Films by SF6 Plasma Treatment

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 236 ◽  
Author(s):  
Yumeng Xu ◽  
Baoxue Bo ◽  
Xin Gao ◽  
Zhongliang Qiao

The passivation effects of SF6 plasma on zinc oxide (ZnO) films prepared by magnetron sputtering were researched. After the SF6 plasma passivation of ZnO films, the grain size increases, there is low surface roughness, and a small amount of Zn-F bonds are formed, resulting in the narrowing of band gap. The photoluminescence (PL) intensity of SF6-passivated ZnO films has a 120% increase compared to the untreated samples, and the reduction in defects can increase the resistivity and stability of ZnO films. ZnO films are used in the preparation of ZnO/p-Si heterojunction diodes. The results of the measurement of current voltage (J–V) show that the reverse current is reduced after SF6 plasma passivation, indicating an improvement in the electrical properties of ZnO films.

1986 ◽  
Vol 77 ◽  
Author(s):  
S. N. Venkatesh ◽  
E. S. Ramakrishnan ◽  
K. C. Jungling ◽  
S. B. Krupanidhi

ABSTRACTHighly crystalline and c-axis oriented zinc oxide thin films were sputter deposited from a ceramic target using rf diode and magnetron sputtering techniques. A comparative evaluation of structure and electrical characteristics of ZnO films in the MZS and MZOS configurations is presented and the results are discussed. The physical and electrical properties were significantly influenced by highly energetic particles originating from the presence of oxygen neutrals in the plasma during the growth process and the behavior differed between the diode and magnetron sputtering processes.


MRS Advances ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 111-117
Author(s):  
José Bruno Cantuária ◽  
Giovani Gozzi ◽  
Lucas Fugikawa Santos

AbstractZinc oxide (ZnO) is a n-type transparent semiconductor which can be processed by low cost techniques (such as spray-pyrolysis and spin-coating) and can be applied as the active layer of thin-films transistors (TFTs). The electrical properties of ZnO films are strongly affected when the device is exposed to room conditions and/or UV-light, suggesting possible applications as UV or/and gas sensors. Atmospheric oxygen molecules adsorbed on ZnO surface act as charge traps, decreasing the material conductivity. The incidence of UV-light causes an increase of the material conductivity due to the photogeneration of electron-hole pairs via direct band-to-band transitions (classic photoconductivity process) and due to the desorption of oxygen molecules, which presents a relatively slower response and is a less understood mechanism. In the current paper, we study the influence of environmental parameters, such as temperature, humidity and UV-light intensity, on the electrical properties of spin-coated ZnO thin films to understand the role of the desorption mechanism on the photoconductivity process. The analysis of the device current vs. time curves shows the existence of two light-induced desorption mechanisms: i) one which increases the electrical conductivity of the ZnO film (desorption-like process) and ii) a second one which decreases the conductivity (adsorption-like process). A Plackett-Burman design of experiment (DOE) was used to study the influence of characterization factors like UV intensity, temperature and humidity on electrical parameters obtained from the experimental curves. We observed that the desorption-like process is a first order mechanism, exhibiting desorption rate proportional to n(t), where n(t) represents the adsorbate concentration as a function of the time, whereas the adsorption-like mechanism exhibits a desorption rate proportional to the forth power of n(t).


2013 ◽  
Vol 591 ◽  
pp. 54-60
Author(s):  
Xiu Li Fu ◽  
Yan Xu Zang ◽  
Zhi Jian Peng

The effect of WO3doping on microstructural and electrical properties of ZnO-Pr6O11based varistor materials was investigated. The doped WO3plays a role of inhibitor in ZnO grain growth, resulting in decreased average grain size from 2.68 to 1.68 μm with increasing doping level of WO3from 0 to 0.5 mol%. When the doping level of WO3was lower than 0.05 mol%, the nonlinear current-voltage characteristics of the obtained varistors could be improved significantly with increasing amount of WO3doped. But when the doping level of WO3became higher, their nonlinear current-voltage performance would be dramatically deteriorated when more WO3was doped. The optimum nonlinear coefficient, varistor voltage, and leakage current of the samples were about 13.71, 710 V/mm and 13 μA/cm2, respectively, when the doping level of WO3was in the range from 0.03 to 0.05 mol%.


2011 ◽  
Vol 239-242 ◽  
pp. 777-780
Author(s):  
Ting Zhi Liu ◽  
Shu Wang Duo ◽  
C Y Hu ◽  
C B Li

ZnO films were deposited on nanostructured Al (n-Al) /glass substrate by RF magnetron sputtering. The results shows that the relation (I (002) /I (100) ≈ I annealed (002)/I annealed (100) ≈1.1) shows the rough n-Al surface is suitable for the growth of a-axis orientation. Meanwhile, the influences of substrate roughness, crystallinity and (101) plane of ZnO film deposited on n-Al layer have been discussed. XPS implies more oxygen atoms are bound to Aluminum atoms, which result in the increase of high metallic Zn in the film.


2015 ◽  
Vol 1115 ◽  
pp. 422-425
Author(s):  
Souad A.M. Al-Bat’hi ◽  
Maizatulnisa Othman

This investigation deals with the effect of temperature on the optical and morphological properties of Zinc Oxide thin films prepared by radio-Frequency (RF) magnetron sputtering technique. In the present work, zinc oxide (ZnO) thin films have been deposited on glass substrates from 50°C to 300°C by radio frequency magnetron sputtering. The effects of deposition temperature on the crystallization behaviour and optical properties of the films have been studied. The thin films were characterized using Ultraviolet Visible Spectroscopy (UV-VIS), Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction Analysis (XRD). From the UV-VIS testing, the average transmission percentage of the films is between 80-95% for all deposition temperatures meanwhile the energy gap of ZnO thin films varies from 3.26 eV to 3.35 eV which is not much different from the theoretical value. Also, the grain size is getting smaller from 3.886nm, 3.216nm, 3.119nm and 3.079nm with respect to the increasing deposition temperature 50°C, 100°C, 200°C and 300°C respectively whereas the average grain size per intercept value is increasing. The patterns of the peak were about the same for all deposition temperature where the thin films have polycrystalline hexagonal wurtzite structure with the orientation perpendicular (002) to the substrate surface (c-axis orientation) at 34.5(2θ).


2013 ◽  
Vol 1494 ◽  
pp. 127-132
Author(s):  
Kanji Yasui ◽  
Naoya Yamaguchi ◽  
Eichi Nagatomi ◽  
Souichi Satomoto ◽  
Takahiro Kato

ABSTRACTZinc oxide (ZnO) with excellent crystallinity and large electron mobility was grown on aplane (11-20) sapphire (a-Al2O3) substrates by a new chemical vapor deposition method via the reaction between dimethylzinc (DMZn) and high-energy H2O produced by a Pt-catalyzed H2-O2 reaction. The electron mobility at room temperature increased from 30 cm2/Vs to 189 cm2/Vs with increasing film thickness from 0.1 μm to approximately 3 μm. Electron mobility increased significantly with decreasing temperature to approximately 110 – 150 K, but decreased at temperatures less than 100 K for films greater than 500 nm in thickness. On the other hand, the mobility hardly changed with temperature for films lesser than 500 nm in thickness. Based on the dependence of the electrical properties on the film thickness, the ZnO films grown on a-Al2O3 substrates are considered to consist of an interfacial layer with a high defect density (degenerate layer) generated due to a large lattice mismatch between ZnO and Al2O3 substrates and an upper layer with a low defect density.


2017 ◽  
Vol 16 (01) ◽  
pp. 1650024
Author(s):  
Bhavana Singh ◽  
S. B. Shrivastava ◽  
V. Ganesan

The work deals with the preparation of Zinc Oxide (ZnO) thin films on microscopic glass substrate by spray pyrolysis technique. The systematic study on the influence of Mn doping up to 15% has been performed. The structural studies revealed that pure and doped film has hexagonal structure. In order to reduce the internal strain due to Mn doping, the crystallite size decreases. The atomic force microscopy (AFM) measurement shows the decrease in grain size and roughness with doping. The resistivity curve shows a clear hump corresponding to smaller Mn doping ([Formula: see text]) around [Formula: see text]. This hump was found to reduce with the increase in Mn concentration and for [Formula: see text], beyond which it vanishes completely. This is attributed to critical behavior of resistivity and may be due to the scattering of carriers by magnetic spin fluctuation via exchange interaction. The optical measurement shows the shift in absorption edge of Mn doped ZnO films toward the longer wavelength side. This correlates the reduction in grain size as a function of Mn concentration. The optical bandgap goes down, whereas refractive index increases with dopant concentration.


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