Optical Properties of Anatase, Rutile and Amorphous Phases of TiO2 Thin Films Grown at Room Temperature by RF Magnetron Sputtering

2002 ◽  
Vol 755 ◽  
Author(s):  
V. M. Naik ◽  
D. Haddad ◽  
R. Naik ◽  
J. Benci ◽  
G. W. Auner

ABSTRACTAnatase (A), rutile (R) and amorphous phase TiO2 thin films have been prepared by RF magnetron sputtering on unheated glass substrates by controlling the total pressure of sputtering gases (Ar + O2) and the substrate bias. The crystal structures of the films were confirmed by x-ray diffraction and Raman scattering. The analysis of optical absorption data for A- TiO2 film shows an energy bandgap (Eg) of 3.2 eV (indirect extrapolation) and ∼ 3.5 eV (direct extrapolation). On the other hand, R-TiO2 film shows Eg ∼ 2.9 eV (indirect) and 3.2 eV (direct). The latter film also shows the presence of amorphous regions with Eg ∼ 3.0 eV (indirect) and 3.8 eV (direct). The bandgap of both the films, obtained using indirect extrapolation, has a value range consistent with the previous measurements.

2018 ◽  
Vol 24 (8) ◽  
pp. 5866-5871 ◽  
Author(s):  
G Balakrishnan ◽  
J. S. Ram Vinoba ◽  
R Rishaban ◽  
S Nathiya ◽  
O. S. Nirmal Ghosh

Nickel oxide (NiO) thin films were deposited on glass substrates using the RF magnetron sputtering technique at room temperature. The Argon and oxygen flow rates were kept constant at 10 sccm and 5 sccm respectively. The films were annealed at various temperatures (RT-300 °C) and its influence on the microstructural, optical and electrical properties were investigated. The X-ray diffraction (XRD) investigation of NiO films indicated the polycrystallinity of the films with the (111), (200) and (220) reflections corresponding to the cubic structure of NiO films. The crystallite size of NiO films was in the range ~4–14 nm. The transmittance of the films increased from 20 to 75% with increasing annealed temperature. The optical band gap of the films was 3.6–3.75 eV range for the as-deposited and annealed films. The Hall effect studies indicated the p-type conductivity of films and the film annealed at 300 °C showed higher carrier concentration (N), high conductivity (σ) and high mobility (μ) compared to other films. These NiO films can be used as a P-type semiconductor material in the devices require transparent conducting films.


2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Savita Sharma ◽  
Monika Tomar ◽  
Nitin K. Puri ◽  
Vinay Gupta

Tungsten trioxide (WO3) thin films were deposited by Rf-magnetron sputtering onto Pt interdigital electrodes fabricated on corning glass substrates. NO2 gas sensing properties of the prepared WO3 thin films were investigated by incorporation of catalysts (Sn, Zn, and Pt) in the form of nanoclusters. The structural and optical properties of the deposited WO3 thin films have been studied by X-ray diffraction (XRD) and UV-Visible spectroscopy, respectively. The gas sensing characteristics of all the prepared sensor structures were studied towards 5 ppm of NO2 gas. The maximum sensing response of about 238 was observed for WO3 film having Sn catalyst at a comparatively lower operating temperature of 200°C. The possible sensing mechanism has been highlighted to support the obtained results.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Abdalla A. Alnajjar

Al-doped ZnO thin films were deposited from two different targets. Ceramic targets were used in RF magnetron sputtering, whereas pulsed magnetron sputtering was used to grow films from powder targets. ZnO:Al films with different thicknesses were sputtered directly on soda-lime glass substrates. The film thickness was in the 0.04–2.0 μm range. The microstructure, such as the grain size and the texture, of the two differently grown ZnO:Al transparent conductive oxide films of different thickness, was studied using X-ray diffractionθ/2θscans. The optical properties, such as the transmittance and reflectance, were measured using a UV-Vis-NIR spectrometer. Further, the sheet resistance, resistivity, carrier concentration, and Hall mobility of these ZnO:Al thin films were measured as a function of film thickness. These results obtained from the two different deposition techniques were compared and contrasted.


2020 ◽  
Vol 1012 ◽  
pp. 119-124
Author(s):  
Paulo Victor Nogueira da Costa ◽  
Rodrigo Amaral de Medeiro ◽  
Carlos Luiz Ferreira ◽  
Leila Rosa Cruz

This work investigates the microstructural and morphological changes on CIGS thin films submitted to a post-deposition heat treatment. The CIGS 1000 nm-thick films were deposited at room temperature by RF magnetron sputtering onto glass substrates covered with molybdenum films. After deposition, the samples were submitted to a heat treatment, with temperatures ranging from 450 to 575 oC. The treatment was also carried out under a selenium atmosphere (selenization), from 400 to 500 oC. Morphological analyzes showed that the as-deposited film was uniform and amorphous. When the treatment was carried out without selenization, the crystallization occurred at or above 450 oC, and the grains remained nanosized. However, high temperatures led to the formation of discontinuities on the film surface and the formation of extra phases, as confirmed by X-ray diffraction data. The crystallization of the films treated under selenium atmosphere took place at lower temperatures. However, above 450 °C the film surface was discontinuous, with a lot of holes, whose amount increased with the temperature, showing that the selenization process was very aggressive. X-ray diffraction analyses showed that the extra phases were eliminated during selenization and the films had a preferential orientation along [112] direction. The results indicate that in the manufacturing process of solar cells, CIGS films deposited at room temperature should be submitted to a heat treatment carried out at 450 °C (without selenization) or 400 °C (with selenization).


Surfaces ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 106-114
Author(s):  
Yannick Hermans ◽  
Faraz Mehmood ◽  
Kerstin Lakus-Wollny ◽  
Jan P. Hofmann ◽  
Thomas Mayer ◽  
...  

Thin films of ZnWO4, a promising photocatalytic and scintillator material, were deposited for the first time using a reactive dual magnetron sputtering procedure. A ZnO target was operated using an RF signal, and a W target was operated using a DC signal. The power on the ZnO target was changed so that it would match the sputtering rate of the W target operated at 25 W. The effects of the process parameters were characterized using optical spectroscopy, X-ray diffraction, and scanning electron microscopy, including energy dispersive X-ray spectroscopy as well as X-ray photoelectron spectroscopy. It was found that stoichiometric microcrystalline ZnWO4 thin films could be obtained, by operating the ZnO target during the sputtering procedure at a power of 55 W and by post-annealing the resulting thin films for at least 10 h at 600 °C. As FTO coated glass substrates were used, annealing led as well to the incorporation of Na, resulting in n+ doped ZnWO4 thin films.


2015 ◽  
Vol 833 ◽  
pp. 127-133
Author(s):  
Jie Yu ◽  
Jie Xing ◽  
Xiu Hua Chen ◽  
Wen Hui Ma ◽  
Rui Li ◽  
...  

La0.9Sr0.1Ga0.8Mg0.2O3-δ (LSGM) electrolyte thin films were fabricated on La0.7Sr0.3Cr0.5Mn0.5O2.75 (LSCM) porous anode substrates by Radio Frequency (RF) magnetron sputtering method. The compatibility between LSGM and LSCM was examined. Microstructures of LSGM thin films fabricated were observed by scanning electron microscope (SEM). The effect of substrate temperature on LSGM thin films was clarified by X-ray Diffraction (XRD). Deposition rate increases firstly at the range of 50°C~150°C, and then decreases at the range of 150°C ~300°C. After annealing, perovskite structure with the same growth orientation forms at different substrate temperature. Crystallite size decreases at first, to the minimum point at 150°C, then increases as substrate temperature rises.


2014 ◽  
Vol 908 ◽  
pp. 124-128 ◽  
Author(s):  
S.B. Chen ◽  
Z.Y. Zhong

Thin films of transparent conducting gallium and titanium doped zinc oxide (GTZO) were prepared on glass substrates by magnetron sputtering technique using a sintered ceramic target. The microstructural properties of the deposited thin films were characterized with X-ray diffraction (XRD). The results demonstrated that the polycrystalline GTZO thin films consist of the hexagonal crystal structures with c-axis as the preferred growth orientation normal to the substrate, and that the working pressure significantly affects the crystal structures of the thin films. The GTZO thin film deposited at the working pressure of 0.4 Pa has the best crystallinity, the largest grain size and the lowest stress.


Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1183
Author(s):  
Peiyu Wang ◽  
Xin Wang ◽  
Fengyin Tan ◽  
Ronghua Zhang

Molybdenum disulfide (MoS2) thin films were deposited at different temperatures (150 °C, 225 °C, 300 °C, 375 °C, and 450 °C) on quartz glass substrates and silicon substrates using the RF magnetron sputtering method. The influence of deposition temperature on the structural, optical, electrical properties and deposition rate of the obtained thin films was investigated by X-ray diffraction (XRD), Energy Dispersive Spectrometer (EDS), Raman, absorption and transmission spectroscopies, a resistivity-measuring instrument with the four-probe method, and a step profiler. It was found that the MoS2 thin films deposited at the temperatures of 150 °C, 225 °C, and 300 °C were of polycrystalline with a (101) preferred orientation. With increasing deposition temperatures from 150 °C to 300 °C, the crystallization quality of the MoS2 thin films was improved, the Raman vibrational modes were strengthened, the deposition rate decreased, and the optical transmission and bandgap increased. When the deposition temperature increased to above 375 °C, the molecular atoms were partially combined with oxygen atoms to form MoO3 thin film, which caused significant changes in the structural, optical, and electrical properties of the obtained thin films. Therefore, it was necessary to control the deposition temperature and reduce the contamination of oxygen atoms throughout the magnetron sputtering process.


2012 ◽  
Vol 1394 ◽  
Author(s):  
Coralie Charpentier ◽  
Patricia Prod’Homme ◽  
Loïc Francke ◽  
Pere Roca i Cabarrocas

ABSTRACTAluminum-doped zinc oxide (ZnO:Al) thin films were prepared on glass substrates by radio frequency (RF) magnetron sputtering from a ceramic mixed target ZnO:Al2O3 (1 wt.%) with a power of 250 W. Two series of samples were deposited at room temperature, the first one in pure Ar atmosphere, the second one in Ar/O2 gas mixture. Effects of post-deposition annealing treatments carried out from 400 °C to 500 °C under vacuum and in N2/H2 (5%) atmosphere have been investigated. The influence of these parameters was studied by a detailed microstructural analysis using X-Ray diffraction and Raman spectroscopy. For N2/H2 annealing process, the increase of charge carrier concentration limits the increase of the mobility while after vacuum annealing, an improvement of both electrical and optical properties was observed. The increase of the crystallinity and grain size for ZnO:Al films deposited in Ar/O2 gas mixture could explain their improvements. Resistivity was reduced down to 3.5×10-4 Ω.cm, for a mobility of 49 cm2/V.s with a vacuum annealing at 450 °C for ZnO:Al deposited in Ar/O2 gas mixture.


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