scholarly journals Structural, Optical and Electrical Properties of Cu doped ZnO Thin Films Grown by RF Magnetron Sputtering: Application to Solar Photocatalysis

Author(s):  
Bilel Khalfallah ◽  
I. Riahi ◽  
F. Chaabouni

Abstract RF sputtered undoped and Cu doped ZnO (CZO) thin films were deposited on unheated glass substrates using a mixed Cu2O and ZnO powders target at different Cu concentrations of 0, 1, 2, 3 and 4 wt.%. The effects of copper concentration on the structural, electrical, optical and photocatalytic properties of CZO films have been studied. From XRD and Raman spectroscopy studies, it was found that the deposited films were polycrystalline with a predominant hexagonal wurtzite structure along the c-axis perpendicular to the substrate surface. The presence of multiple interference fringes in the transmittance and reflectance spectra shows the good homogeneity of the films. All the films are highly transparent with transparency reaching 80% indicating the possibility to use these films as an optical window. The absorption tail gradually shifted towards a higher wavelength side, which resulted in the decrease of bandgap energy from 3.35 to 3.26 eV. All the sputtered films are highly conductive with a conductivity reaching 104 S.cm− 1.The effect of Cu-doping on the photocatalytic activity of ZnO thin films for the degradation of methylene blue (MB) dye was studied under sunlight irradiation and the results showed that the Cudoping provokes appreciable degradation of MB and reached a maximum for the 1 wt.% Cu doped ZnO film.

2011 ◽  
Vol 194-196 ◽  
pp. 2305-2311
Author(s):  
Ying Ge Yang ◽  
Dong Mei Zeng ◽  
Hai Zhou ◽  
Wen Ran Feng ◽  
Shan Lu ◽  
...  

In this study high quality of Al doped ZnO (ZAO) thin films were prepared by RF magnetron sputtering on glass substrates at room temperature in order to study the thickness effect upon their structure, electrical and optical properties. XRD results show that the films are polycrystalline and with strongly preferred (002) orientation perpendicular to substrate surface whatever the thickness is. The crystallite size was calculated by Williamson-Hall method, while it increases as the film thickness increased. The lattice stress is mainly caused by the growth process. Hall measurements revealed electrical parameter very dependent upon thickness when the thickness of ZAO film is lower than 700 nm. The resistivity decreased and the carrier concentration and Hall mobility increases as the film thickness increased. When film thickness becomes larger, only a little change in the above properties was observed. All the films have high transmittance above 90% in visible range. Red shift of the absorption edge was observed as thickness increased. The optical energy bandgap decreased from 3.41eV to 3.30 eV with the increase of film thickness.


2012 ◽  
Vol 626 ◽  
pp. 163-167
Author(s):  
Samsiah Ahmad ◽  
Nor Diyana Md Sin ◽  
M.N. Berhan ◽  
Mohamad Rusop

Zinc oxide thin films were prepared at room temperature in pure argon ambient on glass substrates by RF magnetron sputtering. The effect of sputtering power (50~250 Watt) on the structural properties of the film were investigated. The thickness of ZnO thin films was measured using surface profiler (Dektak 150+). Atomic force microscopy machine (AFM-Park system XE-100) was used to characterize the morphology while the crystalinity have been characterized using XRD (Rigaku Ultima IV). It was found that the thickness, growth rate and RMS roughness increases with increasing RF power. All films exhibit the (002) plane which correspond to hexagonal wurtzite structure with the highest peak at 150 Watt.


2013 ◽  
Vol 665 ◽  
pp. 159-167
Author(s):  
M.S. Jani ◽  
H.S. Patel ◽  
J.R. Rathod ◽  
K.D. Patel ◽  
V.M. Pathak ◽  
...  

In this paper structural and optical properties of CdSe thin films with different thickness deposited by thermal evaporation under vacuum onto glass substrates are presented. The structural investigations performed by means of XRD technique showed that the films have a polycrystalline and hexagonal (würtzite) structure. The values of some important parameters of the studied films (absorption coefficient and optical bandgap energy) are determined from transmission spectra. The values of the optical bandgap energy (Eg) calculated from the absorption spectra, ranged between 1.67 - 1.74 eV.


Author(s):  
Feri Adriyanto

<p class="Abstract">The Ar flow rate effect on the electrical and optical properties of the sputtered Al-doped ZnO thins films were investigated. It was shown that a strong X-ray peak from (002) and (004) planes is dominant, suggesting that most grains have <em>c</em>-axis perpendicular to the substrate surface. The (002)-ZnO and (004)-ZnO peaks were measured at 2q = 34.12<sup>0</sup>, and 71.85<sup>0</sup>, respectively. It was also found that the growth rate of the Al-doped ZnO thin films increases when the sputtering power is increased. The transmittance of these film are strongly dependent on the sputtering power with the maximum transmittance of 92% was obtained at the sputtering power of 150 W and 50 sccm of Ar flow rate. The resistivity of the films is decreases as the Ar flow rate is increased. The lowest resistivity of 9.74 x 10<sup>-4</sup> W.cm was obtained at the films with Ar flow rate of 80 sccm. The mobility increases with the Ar flow rate increases. The carrier concentration also indicates the same pattern as the mobility. The transmittance of Al-doped ZnO thin films is also strongly dependent on the Ar flow rate. It was also observed the variation of contact resistivity of Al/Ti/Al to Al-doped n-ZnO thin films. The specific contact resistivity <em>r<sub>c</sub></em> of 1.8x10<sup>−5</sup> W.cm<sup>2</sup> was obtained at 150 nm-thick Al.</p>


2018 ◽  
Vol 6 (3) ◽  
pp. 588-597 ◽  
Author(s):  
Dominic B. Potter ◽  
Michael J. Powell ◽  
Ivan P. Parkin ◽  
Claire J. Carmalt

Aluminium/gallium co-doped ZnO (AGZO), indium/gallium co-doped ZnO (IGZO), and aluminium/indium co-doped ZnO (AIZO) thin films were synthesised on glass substrates via aerosol assisted chemical vapour deposition (AACVD).


2021 ◽  
Author(s):  
Chunhu Zhao ◽  
Junfeng Liu ◽  
Yixin Guo ◽  
Yanlin Pan ◽  
Xiaobo Hu ◽  
...  

Abstract Aluminum doped ZnO thin films (AZO), which simultaneously transmit light and conduct electrical current, are widely applied in photovoltaic devices. To achieve high performance AZO thin films, the effects of RF magnetron sputtering conditions on the optical and electrical properties of the films has been explored. The optimized AZO thin films exhibit strong (002) orientated growth with hexagonal wurtzite structure. The minimum resistivity of 0.9Í10-3 Ω·cm, the highest carrier concentration of 2.8Í1020 cm-3, the best Hall mobility of 22.8 cm2·(V·s)-1 and average transmittance above 85% can be achieved at the optimum deposition condition of 0.2 Pa, 120 W and 200 °C. Considering the single parabolic band model, the bandgap shift by carrier concentration of the films can be attributed to the Burstein-Moss effect. The results indicate that RF magnetron sputtered AZO thin films are promising for solar cell applications relying on front contact layers.


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