NANOFIBERS IN CdTe: IODINE THIN FILMS BY SPRAY DEPOSITION

2005 ◽  
Vol 04 (04) ◽  
pp. 725-729 ◽  
Author(s):  
RANGARAO ARNEPALLI ◽  
VIRESH DUTTA

Cadmium Telluride: Iodine nanoparticle thin films were prepared by spraying iodine doped CdTe nanoparticles dispersed in 1-Butanol, on the glass substrates kept at 200°C for 20 min. Iodine doped CdTe nanoparticles had been prepared by adding trace amounts of Iodine powder in addition to stoichiometric ratios of Cd and Te in the Solvothermal synthesis. The films were prepared by applying without a voltage and with a voltage of 700 V to the nozzle during the deposition. The presence of iodine in the films was confirmed by the sign of voltage generated (positive relative to the cold end) in the hot probe method and also from the elemental analysis using X-ray Photoelectron Spectroscopy. X-ray diffraction patterns of the films showed predominantly Hexagonal CdTe peaks in both the cases. From the transmission spectra of the films the bandgap was found to be 1.77 eV against the bulk CdTe bandgap of 1.5 eV. The band edge was not as sharp as compared to that in case of the undoped films. SEM and TEM micrographs of both the films revealed the formation of Nanofibers.

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.


2009 ◽  
Vol 68 ◽  
pp. 69-76 ◽  
Author(s):  
S. Thanikaikarasan ◽  
T. Mahalingam ◽  
K. Sundaram ◽  
Tae Kyu Kim ◽  
Yong Deak Kim ◽  
...  

Cadmium iron selenide (Cd-Fe-Se) thin films were deposited onto tin oxide (SnO2) coated conducting glass substrates from an aqueous electrolytic bath containing CdSO4, FeSO4 and SeO2 by potentiostatic electrodeposition. The deposition potentials of Cadmium (Cd), Iron (Fe), Selenium (Se) and Cadmium-Iron-Selenide (Cd-Fe-Se) were determined from linear cathodic polarization curves. The deposited films were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive analysis by x-rays (EDX) and optical absorption techniques, respectively. X-ray diffraction patterns shows that the deposited films are found to be hexagonal structure with preferential orientation along (100) plane. The effect of FeSO4 concentration on structural, morphological, compositional and optical properties of the films are studied and discussed in detail.


2015 ◽  
Vol 1117 ◽  
pp. 139-142 ◽  
Author(s):  
Marius Dobromir ◽  
Radu Paul Apetrei ◽  
A.V. Rogachev ◽  
Dmitry L. Kovalenko ◽  
Dumitru Luca

Amorphous Nb-doped TiO2 thin films were deposited on (100) Si and glass substrates at room temperature by RF magnetron sputtering and a mosaic-type Nb2O5-TiO2 sputtering target. To adjust the amount of the niobium dopant in the film samples, appropriate numbers of Nb2O5 pellets were placed on the circular area of the magnetron target with intensive sputtering. By adjusting the discharge conditions and the number of niobium oxide pellets, films with dopant content varying between 0 and 16.2 at.% were prepared, as demonstrated by X-ray photoelectron spectroscopy data. The X-ray diffraction patterns of the as-deposited samples showed the lack of crystalline ordering in the samples. Surfaces roughness and energy band gap values increase with dopant concentration, as showed by atomic force microscopy and UV-Vis spectroscopy measurements.


Author(s):  
Mohammad Ghaffar Faraj

Lead sulfide (PbS) thin films of different molarities (0.05 M, 0.075 M and 0.1 M) were prepared on glass substrates at 325 °C by chemical spray pyrolysis (CSP) technique. X-ray diffraction patterns confirm the proper phase formation of the PbS. The X-ray diffraction patterns’ results reveal that the all of PbS films have a face centered cubic structure with preferential reflection of (200) plane. The crystallite grain size was calculated using Scherrer formula and it is found that the 0.1M has maximum crystallite grain size (37.4 nm). Depending on the molarity, Hall measurement showed that the electrical resistivity and mobility at room temperature varied in the range 6.3x103Ω.cm to 2.1x103Ω.cm and 4.79cm2/V.S to 24.3 cm2/V.S.


Coatings ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 107 ◽  
Author(s):  
San-Ho Wang ◽  
Sheng-Rui Jian ◽  
Guo-Ju Chen ◽  
Huy-Zu Cheng ◽  
Jenh-Yih Juang

The effects of annealing temperature on the structural, surface morphological and nanomechanical properties of Cu-doped (Cu-10 at %) NiO thin films grown on glass substrates by radio-frequency magnetron sputtering are investigated in this study. The X-ray diffraction (XRD) results indicated that the as-deposited Cu-doped NiO (CNO) thin films predominantly consisted of highly defective (200)-oriented grains, as revealed by the broadened diffraction peaks. Progressively increasing the annealing temperature from 300 to 500 °C appeared to drive the films into a more equiaxed polycrystalline structure with enhanced film crystallinity, as manifested by the increased intensities and narrower peak widths of (111), (200) and even (220) diffraction peaks. The changes in the film microstructure appeared to result in significant effects on the surface energy, in particular the wettability of the films as revealed by the X-ray photoelectron spectroscopy and the contact angle of the water droplets on the film surface. The nanoindentation tests further revealed that both the hardness and Young’s modulus of the CNO thin films increased with the annealing temperature, suggesting that the strain state and/or grain boundaries may have played a prominent role in determining the film’s nanomechanical characterizations.


2005 ◽  
Vol 20 (8) ◽  
pp. 2127-2139 ◽  
Author(s):  
F. Tyholdt ◽  
S. Jørgensen ◽  
H. Fjellvåg ◽  
A.E. Gunnæs

Textured, thin films of BiFeO3 (∼120 nm thickness) were synthesized by chemical solution deposition from a mixture of iron- and bismuth- 2-methoxyethoxides on Si(100)/SiO2/TiO2/Pt substrates. The use of alkoxides ensured good homogeneity and a low degree of organics that further facilitated low crystallization temperatures. Crystalline films were according to x-ray diffraction already obtained at 480 °C. Precursor characteristics were investigated using thermogravimetry and differential scanning calorimetry, whereas phase purity, microstructure and film topography were examined by x-ray diffraction, transmission electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy. A small (10%) Bi excess was found necessary to obtain dense, pore-free films. Such additions also prevented decomposition of BiFeO3 at high temperatures. The observed (012) texture is believed to originate from the growth mechanism as no relation to the substrate is found. This is also confirmed by observing (012) texture for films on glass substrates.


2021 ◽  
Vol 903 ◽  
pp. 51-56
Author(s):  
Lavanya Mekala ◽  
Sunita Ratnam Srirangam ◽  
Rajesh Kumar Borra ◽  
Subba Rao Thota

In the present work, reactive DC magnetron sputtering method is used to deposit TiO2 thin films on glass substrates. The structural, surface morphology and optical studies of TiO2 thin films were discussed by varying the oxygen flow rates from 1 to 4 sccm. X-ray diffraction patterns of TiO2 thin films show amorphous nature. The surface morphological and elemental composition of TiO2 thin films were examined by field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. From the optical absorption spectra, the shifting of absorption edge towards the longer wavelength leads to the decrement of optical bandgap from 3.48 to 3.19 eV with an increase of oxygen flow rate from 1 to 4 sccm.


2019 ◽  
Vol 15 (34) ◽  
pp. 1-14
Author(s):  
Bushra A. Hasan

Lead selenide PbSe thin films of different thicknesses (300, 500, and 700 nm) were deposited under vacuum using thermal evaporation method on glass substrates. X-ray diffraction measurements showed that increasing of thickness lead to well crystallize the prepared samples, such that the crystallite size increases while the dislocation density decreases with thickness increasing. A.C conductivity, dielectric constants, and loss tangent are studied as function to thickness, frequency (10kHz-10MHz) and temperatures (293K-493K). The conductivity measurements confirm confirmed that hopping is the mechanism responsible for the conduction process. Increasing of thickness decreases the thermal activation energy estimated from Arhinus equation is found to decrease with thickness increasing. The increase of thickness lead to reduce the polarizability α while the increasing of temperature lead to increase α.


Author(s):  
Tianlei Ma ◽  
Marek Nikiel ◽  
Andrew G. Thomas ◽  
Mohamed Missous ◽  
David J. Lewis

AbstractIn this report, we prepared transparent and conducting undoped and molybdenum-doped tin oxide (Mo–SnO2) thin films by aerosol-assisted chemical vapour deposition (AACVD). The relationship between the precursor concentration in the feed and in the resulting films was studied by energy-dispersive X-ray spectroscopy, suggesting that the efficiency of doping is quantitative and that this method could potentially impart exquisite control over dopant levels. All SnO2 films were in tetragonal structure as confirmed by powder X-ray diffraction measurements. X-ray photoelectron spectroscopy characterisation indicated for the first time that Mo ions were in mixed valence states of Mo(VI) and Mo(V) on the surface. Incorporation of Mo6+ resulted in the lowest resistivity of $$7.3 \times 10^{{ - 3}} \Omega \,{\text{cm}}$$ 7.3 × 10 - 3 Ω cm , compared to pure SnO2 films with resistivities of $$4.3\left( 0 \right) \times 10^{{ - 2}} \Omega \,{\text{cm}}$$ 4.3 0 × 10 - 2 Ω cm . Meanwhile, a high transmittance of 83% in the visible light range was also acquired. This work presents a comprehensive investigation into impact of Mo doping on SnO2 films synthesised by AACVD for the first time and establishes the potential for scalable deposition of SnO2:Mo thin films in TCO manufacturing. Graphical abstract


1995 ◽  
Vol 382 ◽  
Author(s):  
Martin Pehnt ◽  
Douglas L. Schulz ◽  
Calvin J. Curtis ◽  
Helio R. Moutinho ◽  
Amy Swartzlander ◽  
...  

ABSTRACTIn this article we report the first nanoparticle-derived route to smooth, dense, phase-pure CdTe thin films. Capped CdTe nanoparticles were prepared by injection of a mixture of Cd(CH3)2, (n-C8H17)3 PTe and (n-C8H17)3P into (n-C8H17)3PO at elevated temperatures. The resultant nanoparticles 32-45 Å in diameter were characterized by x-ray diffraction, UV-Vis spectroscopy, transmission electron microscopy, thermogravimetric analysis and energy dispersive x-ray spectroscopy. CdTe thin film deposition was accomplished by dissolving CdTe nanoparticles in butanol and then spraying the solution onto SnO2-coated glass substrates at variable susceptor temperatures. Smooth and dense CdTe thin films were obtained using growth temperatures approximately 200 °C less than conventional spray pyrolysis approaches. CdTe films were characterized by x-ray diffraction, UV-Vis spectroscopy, atomic force microscopy, and Auger electron spectroscopy. An increase in crystallinity and average grain size as determined by x-ray diffraction was noted as growth temperature was increased from 240 to 300 °C. This temperature dependence of film grain size was further confirmed by atomic force microscopy with no remnant nanocrystalline morphological features detected. UV-Vis characterization of the CdTe thin films revealed a gradual decrease of the band gap (i.e., elimination of nanocrystalline CdTe phase) as the growth temperature was increased with bulk CdTe optical properties observed for films grown at 300 °C.


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