Papers by Ankit Kumar Vishwakarma
This paper studied the structural, morphological, optical, near-edge X-ray absorption fine struct... more This paper studied the structural, morphological, optical, near-edge X-ray absorption fine structure spectroscopy (XANES) and sensing properties of a titanium dioxide (TiO 2) thin film. The titanium dioxide thin film was prepared in a thin-film laboratory on a clean glass plate using a physical vapor deposition (PVD) method. The structural, morphological, optical and electronic properties of the fabricated samples were investigated using X-ray diffraction (XRD), atomic force microscopy (AFM), ultraviolet-visible spectroscopy and XANES. It was found from XRD that the crystallite size was~25.66 nm with a microstrain of~0.0064 using the Williamson-Hall plot. The fractal terms such as grain size, roughness, kurtosis and skewness were estimated using AFM. The grain size laid within the nanometric range and was found to be~77.21 nm. The band gap of the fabricated film was~3.23 eV. The XANES analysis was well supported by XRD measurement, and the results showed that the fabricated titanium dioxide thin film was in anatase phase. The sensing properties of titanium dioxide were studied for the detection of liquified petroleum gas (LPG) at concentrations of 0-5000 parts per million at room temperature. The results showed that the titanium dioxide film was highly sensitive and had a fast response as an LPG sensor with a maximum sensitivity of~198%.
Applied Physics A , 2024
The present work deals with the study of the structural and sensing behavior of Sb 2 O 3-doped ti... more The present work deals with the study of the structural and sensing behavior of Sb 2 O 3-doped tin oxide thick film. Three kinds of sensors undoped SnO 2 , 5 wt% Sb 2 O 3-SnO 2, and 15 wt% Sb 2 O 3 doped-SnO 2 are prepared by screen-printed on designed alumina substrate. The structural properties of fabricated sensors are analyzed by using XRD and their sensing behaviors were examined for ethanol gas. The XRD measurement reveals that the average crystallite size of undoped SnO 2 and doped SnO 2 with Sb 2 O 3 composition i.e., 5 wt% Sb 2 O 3-doped SnO 2 and 15 wt% Sb 2 O 3-doped SnO 2 is 28.83 nm, 21.61 nm, and 18.53 nm respectively. The addition of Sb 2 O 3 content in SnO 2 reduces the crystallite size and thus, Sb 2 O 3 doping suppresses SnO 2 crystallite growth. The response of the fabricated sensor is measured with the varying concentration of the ethanol (0-5000 ppm) in the testing chamber at the different operating temperatures of 150 °C, 200 °C, and 250 °C. We observed that Sb 2 O 3 doping improved response and the 15 wt% antimony oxide doped sample showed a maximum response of ~ 73.5% for ethanol gas (5000 ppm) at 250 °C. The experimental result for ethanol gas has been validated with the theoretical model and observed results are found to be in good agreement with that proposed model.
International Journal of Hydrogen Energy
Gas sensors based on metal oxide nanostructures are in demand for the safety of human health and ... more Gas sensors based on metal oxide nanostructures are in demand for the safety of human health and protection from environmental pollution. This type of sensors is more attractive in modern life for electronic devices because of low cast, more efficient, high reliability, fast response, more selective, and simplicity. In this paper we report undoped and PbO doped SnO2 thick film to study its microstructural and sensing behaviours. Three samples have been fabricated using screen printing technique on an alumina substrate and this is SnO2 (S1) and 1wt% PbO doped SnO2 (S2 and S3) at 800 0C and 900 0C. XRD and AFM techniques are used to observe the structural behaviours and it is found that the crystallite size decreases with PbO doping. The sensing properties such as sensing response, selectivity and transient time of the deposited thick films were studied at 200°C for various test gases such as ethanol, LPG and acetone concentrations (0–5000 ppm level). We also found that the response o...
Materials Today: Proceedings
International Journal of Hydrogen Energy
Materials Science in Semiconductor Processing, 2014
Journal of Physics: Conference Series
In this paper, we fabricate two devices, undoped tin oxide (UTO) and 1 wt% palladium-doped tin ox... more In this paper, we fabricate two devices, undoped tin oxide (UTO) and 1 wt% palladium-doped tin oxide (PdTO) thick films for ethanol (C2H5OH) gas sensors. UTO and PdTO samples were deposited on alumina substrate using screen-printing technology. The fabricated UTO and PdTO sample was used as ethanol gas sensor in range (0-5000 ppm) at operating temperature 473 K. The results showed the highest response (∼71%) for varying concentrations of ethanol (5000 ppm) at operating temperature 473 K. Also response/recovery time was observed and it was ∼41 s / 125 s. our experimental data was well supported by the proposed theoretical model.
Environmental Science and Pollution Research, 2020
In the present study, we fabricate undoped and 1 wt% palladium (Pd)-doped tin oxide (SnO2) films ... more In the present study, we fabricate undoped and 1 wt% palladium (Pd)-doped tin oxide (SnO2) films were deposited on alumina substrate using screen printing technology. The deposited sensing film is characterized and its microstructural properties are studied using X-ray diffraction (XRD) and atomic force microscope (AFM). The crystallite size, grain size, and roughness parameter decrease with Pd doping. It was ~ 23.5 nm and ~ 19.2 nm for undoped and Pd-doped SnO2 film samples. The response of fabricated thick film sensor for 1 wt% Pd-doped SnO2 is maximum (~ 71) with varying concentrations of ethanol (5000 ppm) at operating temperature 473 K. The response/recovery time is observed and it is ~ 41 s/125 s. The reduction in crystallinity and roughness leads to improves sensing behavior towards ethanol gas. The sensing mechanism and response behavior is explained based on a theoretical model.
Sensor Letters, 2019
In recent years, significant interest has been shown in the design and development of sensing dev... more In recent years, significant interest has been shown in the design and development of sensing devices which can be used to identify toxic, combustible gases and organic vapors. The detection of air pollutants such as hydrocarbons, which often has to face in everyday life, is the necessity of mankind. In the present study, undoped and the CdS-doped titanium dioxide (CdS–TiO2) thin film has been fabricated on the glass substrate by the thermal evaporation method using High Hind Vacuum coating unit model number 12 A4D. The several samples of different thickness lie in rang (450 μm to 500 μm) were fabricated. The sensing properties of fabricated CdS-doped TiO2 thin film were examined for toluene gas at room temperature (300 K). The response and recovery time of the sensor were measured varying the concentration of toluene (0–5000 ppm) in air ambient and it is 22 for undoped TiO2 and 38 for CdS–TiO2 thin film. The response and recovery time of the sensors is the 70 s and 125 s for expose...
Vacuum, 2019
The present paper reports on fabrication of the undoped and cadmium sulphide (CdS) doped titanium... more The present paper reports on fabrication of the undoped and cadmium sulphide (CdS) doped titanium dioxide (TiO 2) samples (1 wt% CdS-TiO 2 and 2 wt% CdS-TiO 2) and their characterization. Effect of the dopant on microstructural, optical and electronic properties of the fabricated samples are presented by X-ray diffraction (XRD), atomic force microscope (AFM), Raman spectra, UV-visible absorption spectra and X-ray absorption near edge spectroscopy (XANES). XANES spectra of the Ti L edges and O K edges of the CdS-TiO 2 films revealed that with 2 wt% CdS doping in theTiO 2 , crystal structure changes from the anatase type to the rutile type. Ti L edges as well as O K edges both exhibits that 2 wt% CdS doping in TiO 2 has modified the electronic structure of TiO 2. Results of XRD and AFM show that crystallite size and roughness of the TiO 2 significantly reduces with the CdS doping. It is observed from Raman spectra that the peaks shift towards higher wave number with increasing CdS contents indicating decrease in bond lengths. Optical band-gap for the undoped TiO 2 is 3.33 eV and 2.71eV with 2 wt% CdS doped and it is found that absorption band-gap of TiO 2 is red shifted to visible region.
Advanced Science, Engineering and Medicine, 2018
In the present paper, a morphological and optical property of Titanium dioxide (TiO 2 thin film h... more In the present paper, a morphological and optical property of Titanium dioxide (TiO 2 thin film has been studied. A TiO 2 thin film is deposited on glass substrate by physical vapor deposition (PVD) method. The micro structural, optical and electronic properties have been studied by X-ray diffraction (XRD), AFM, U-V absorption and X-ray Absorption Spectroscopy (XAS). The crystallite size of thin film was evaluated using XRD pattern. XRD revealed that TiO 2 existed in the anatase crystalline phase and its crystallite size was 60.77 nm. The morphologies of TiO 2 film were examined by AFM measurement and average grain size and roughness parameter of the films were reported. Using U-V spectra, optical band gap of TiO 2 thin film was calculated and it was found to be 3.2 eV. In the present investigation we observed that the deposited TiO 2 thin films are found to be anatase structure of polycrystalline and crystallite size lies in nanometric range. The XAS measurement of TiO 2 thin film confirms the anatase structure. The fabricated thin film may be used for gas sensing application.
Water science and technology : a journal of the International Association on Water Pollution Research, 2015
CdS doped TiO2 nanotube composite was fabricated by chemical bath deposition, and was characteriz... more CdS doped TiO2 nanotube composite was fabricated by chemical bath deposition, and was characterized by the structural, spectral and photoelectrochemical properties. The results of the structural and spectral properties showed that CdS particles were successfully deposited onto the surface of TiO2 nanotube. It is demonstrated that CdS doped TiO2 nanotube composite improved the light harvesting ability. Power conversion efficiency of about 0.32% was observed. This value is about 2.9 times higher than that of pure TiO2 nanotube. The CdS doped TiO2 nanotube composite possesses relatively higher photocatalytic activity and photodegradation efficiency than that of pure TiO2 nanotube under UV light irradiation, and the degradation efficiency of methyl orange was about 42% at UV intensity of 32 W.
IOP Conference Series: Materials Science and Engineering, 2018
Cadmium Sulphide (CdS) doped Titanium dioxide (TiO2) thick film sensor was produced on alumina su... more Cadmium Sulphide (CdS) doped Titanium dioxide (TiO2) thick film sensor was produced on alumina substrate and their propanol sensing behaviour were investigated. Undoped TiO2 and 2wt% CdS-TiO2 thick film are fabricated on alumina substrate. Sensing properties such as, sensitivity and selectivity measurement are carried out in the range 0- 5000 ppm at room temperature. The results showed that, 2wt% CdS-TiO2 sample gives higher response (60%) for propanol against L.P.G. and ethanol. The response of propanol is 3.75 times more than L.P.G. and 1.94 time of Ethanol. 2wt% CdS-TiO2 sample are more (56.08 %) selective for propanol over L.P.G. and Ethanol. The result obtained indicated that CdS-TiO2 composite thick film may used for propanol sensing.
Materials Today: Proceedings
Materials Today: Proceedings
Materials Today: Proceedings
3RD INTERNATIONAL CONFERENCE ON CONDENSED MATTER AND APPLIED PHYSICS (ICC-2019)
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Papers by Ankit Kumar Vishwakarma