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Introduction
Additional affiliations
July 2020 - present
Position
- Professor (Assistant)
January 2019 - January 2020
November 2012 - November 2018
Publications
Publications (43)
In this manuscript, a thorough comparative analysis of six GaAs based different nanostructures (hollow and solid) is performed on the basis of their optical performance. These nanostructures are known to exhibit excellent anti-reflection properties, owing to their ability to generate a broadband absorption spectrum through efficient photon harvesti...
Conventionally employed resistive mode, vis-à-vis relatively non-conventional capacitive mode measurement technique for ZnO homojunction based alcohol vapor sensor is reported in this paper. ZnO homojunction comprising of sol-gel grown p-ZnO (sodium doped) nanoparticles and electrochemically derived undoped n-ZnO nanotubes was fabricated and after...
In order to meet the demand of rising global power, the research on nanostructured solar cell is gaining momentum at a massive rate. Planar solar cells are less efficient compared to nanostructured solar cells, since nanostructured solar cells have large surface to volume ratio. We have considered GaAs based nanostructures like nanowire (NW), nanoc...
Transduction of the gas sensor devices through Impedance Spectroscopy (IS) provides non-conventional route to derive quantified model of equivalent circuit and to address resonant frequency tuned selectivity aspect. The quantification of the equivalent circuit elements possibly enhances the scientific understandings of sensing performance in comput...
Fast responding room temperature ethanol sensor device, having high detection range, was developed employing dual surface engineered (using palladium (Pd) and Reduced Graphene oxide (RGO)) WO
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nanospheres as the sensing layer. Three different types...
With the advent of industrial renaissance and world population exploration, atmospheric pollution is being elevated beyond the predicted roadmap. Development of effective and inexpensive systems for detection as well as selective quantification of environmentally hazardous species (i.e. NO2, NO, N2O, H2S, CO, NH3, CH4, CO2, volatile organic compoun...
In this paper, an efficient room temperature ethanol sensor device based on p-n homojunction of p-TiO
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nanoparticles (NPs) and n-TiO
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nanotubes (N...
Since their invention, advents in structural evolution of semiconducting metal oxide-based chemical sensors relied much on the controllable surface to volume ratio of different nanoforms as the governing factor for sensing performance. Among the established synthesis techniques, electrochemical anodization has been found to be the promising one to...
Capacitive mode methanol sensing performance of
ZnO hexagonal nanorods based MIS devices having diameters
of 40-60 nm and lengths of 460-480 nm, is reported in this paper.
ZnO nanorods were synthesized on p-Si substrate by chemical
bath deposition method (CBD) using 50 ml aqueous solution of
Zinc acetate dihydrate and HMT. The as deposited sensor w...
A quantitative analysis of equivalent circuit, for Pd/ZnO nanorod/Si based Metal-Insulator-Semiconductor (MIS) device, for sensing 2-propanol, through impedance (|Z|) and phase (φ) measurements, is presented in this paper. The impedance and phase of the MIS device was measured for air and for 50 ppm 2-propanol and the corresponding equivalent circu...
Selective detection of vapor species, specially belonging to the same group, is a crucial bottleneck for resistive sensor devices. In this paper, methanol, ethanol and 2-propanol detection by Pd/TiO2 nanorod array/Ti device in capacitive mode was achieved, with improved selectivity, employing a resonant frequency tuning technique. The optimal capac...
Electrochemically derived partially ruptured TiO₂ nanotubes, under the influence of a high anodization voltage, was synthesized and tested for potential gas sensor application. Low voltage anodization (20 V) resulted in free-standing pristine nanotube array formation, whereas high anodization voltage (60 V) ruptured the nanotubular structure due to...
Selective detection of vapor species, specially
belonging to the same group, is a major constraint for resistive
sensor devices. In this paper, selective alcohol (methanol,
ethanol and 2-propanol) detection of Pd/TiO2 nanorod array/Ti
(Metal-Insulator-Metal) device in capacitive mode was
achieved by a resonant frequency tuning technique. The
resona...
Sensing performance of metal oxide based gas sensor is predominantly governed by the adsorption-desorption kinetics at the adsorption sites which is a function of the truncation of the surface of nanoarchitechtured metal oxide [1]. The adsorption phenomenon, due to its endothermic nature, requires activation energy which is normally supplied either...
High electric field assisted electrochemical anodization of titanium foil to grow TiO2 nanotube array is carried out in this report with an objective to sense carcinogenic aromatic hydrocarbon (benzene, toluene and xylene or BTX) vapor with appreciable response of MIM sensor device configuration. Application of high anodic voltage allows to rupture...
In this paper, highly repeatable aromatic hydrocarbon [such as benzene (B), toluene (T) and xylene (X) (BTX)] sensing performance of Ti/TiO2 nanotube (NT) array/Ti sandwiched device structure, in the capacitive mode, is reported. The sensing layer was synthesized via electrochemical route and the capacitive performance of the device, toward organic...
Highly sensitive ethanol sensing performance of Pd/ZnO nanorods (NRs)/Si MIS device in the capacitive mode is reported in this paper. The MIS device with palladium as the top electrode and silicon as the substrate (bottom) employed ZnO-NRs as the semi-insulating sensing layer. The capacitive changes in the MIS device with exposure to ethanol vapor...
Electrochemical anodization, in potentiostatic mode, with two different applied voltages (20 V and 60 V) has been carried out with Ti foil as anode and graphite rod as cathode. Viscous electrolyte with slight elevated temperature (37°C) was incorporated for dissolution of unwanted byproduct. XRD technique authenticates the purity of grown sample wh...
Present paper concerns, ethanol sensing performance of n-TiO2/p-Si heterojunction devices under different operating temperatures. The heterojunction was fabricated by growing TiO2 oxide layer on p-Si (100) substrate by a dip coating method. Structural characterization like XRD and AFM was carried out to investigate the crystallinity and surface rou...
Capacitive mode methanol sensing performance of ZnO hexagonal nanorods based MIS devices having diameters of 40-60 nm and lengths of 460-480 nm, is reported in this paper. ZnO nanorods were synthesized on p-Si substrate by chemical bath deposition method (CBD) using 50 ml aqueous solution of Zinc acetate dihydrate and HMT. The as deposited sensor w...
Chemically stable, non-toxic and non-stoichiometric titanium dioxide (TiO2) is suitable candidate as gas sensing material with aid of easy and controllable synthesis methods for processing different nanostructures. Among different nanostructures, nanotube is featured to be higher surface area owing to its available gas interaction sites along inner...
This paper concerns development of electrochemically synthesized titanium dioxide (TiO2) nanotube
array for sensing the carcinogenic aromatic hydrocarbons like benzene, toluene, and xylene (BTX) with
enhanced sensitivity achievable at relatively low temperature. Structural characterizations (XRD, FESEM),
revealed that variation of the H2O concentra...
The present study concerns development of an efficient alcohol sensor by controlling the stoichiometry, length, and wall thickness of electrochemically grown TiO2 nanotube array for its use as the sensing layer. Judicious variation of H2O content (0, 2, 10 and 100% by volume) in the mixed electrolyte comprising ethylene glycol and NH4F resulted int...
Sensing performance of sol–gel synthesised p-titania based sensors towards detection of low concentrations (⩽1 ppm) of benzene, toluene and xylene (BTX) at low temperature range (50°–175 °C) is presented in this article. The sensing layer was grown by dip coating method using oxidized silicon wafer as the substrate. X ray diffraction (XRD) analysis...
In this paper, sol-gel derived undoped p-type nano titania thin films particularly aimed to detect low ppm (5–100 ppm) methanol at low temperature (75–150 °C) is reported. Anantase TiO2 thin film was deposited by sol-gel technique and p-type conductivity of the film was confirmed by Hall measurement.
Nanocrystalline structure (12–15 nm) of the TiO2...
In this paper, we report on the development of a highly sensitive, relatively low-temperature ethanol sensor based on sol-gel derived p-TiO2 thin film. The p-type anatase TiO2 thin film was deposited by sol-gel technique on a thermally oxidized <;100> p-Si (resistivity 5 Ω cm) substrate. Anatase TiO2 phase with <;101> nanocrystallinity was confirme...
Titanium foil was anodized electrochemically in three different temperatures to tune the wall thickness of the anodic titanium dioxide (TiO2). XRD analysis of the prepared samples, after annealing, reveals anatase (101) and (204) crystallinity. Variation of bath temperature during electrochemical process effects on wall thickness which is authentic...
The oxygen vacancy (OV) variation of the electrochemically grown TiO2 nanotube (NT) was achieved through stoichiometry variation by varying the volume of water in the electrolyte (NH4F with ethylene glycol) during anodization. By varying the water content (0%, 2%, and 10% by volume) in the mixed electrolyte, the morphology and stoichiometry of NTs...
Present study investigated, the acetone sensing properties of Pd/TiO2/Si Metal Insulator Semiconductor (MIS) devices with nanocrystalline p-TiO2, with crystalline size ~8 nm as the sensing layer. p-TiO2 thin film was synthesized using sol-gel method. After details structural characterization by X-Ray Diffraction (XRD), Field Emission Scanning Elect...
Pointed and blunt tips based ZnO nanoflowers were synthesized and their methanol sensing performance is reported in this paper. Chemical bath deposition (CBD) method was used for escalation of pointed and blunt tips based flower-like nanostructures. 0.1(M) ZnCl2 and NH3 solution (about 25%) with pH of 11 was used as precursor for both the cases. Fo...
Undoped nanocrystalline anatase p-type TiO2 thin film was deposited by sol-gel method on thermally oxidized p-Si (2-5 Omega cm, < 100 >) substrates. The thin film was characterized by X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) to confirm the formation of nanocrystalline anatase titania and to determine the cryst...
Oxygen vacancies, which are predominantly governed by the stoichiometry of the semiconducting metal ox ides, play the pivotal role in determining the gas/vapor species interaction on the oxide surface characteristics [1]. Nanotubes, owing to their very high surface to volume ratio (availability of both inner and outer walls), attracted chemical sen...
Oxygen vacancy (OV) controlled TiO2 nanotubes, having diameters of 50–70 nm and lengths of 200–250 nm, were synthesized by electrochemical anodization in the mixed electrolyte comprising NH4F and ethylene glycol with selective H2O content. The structural evolution of TiO2 nanoforms has been studied by field emission scanning electron microscopy. Va...
A TiO2 nanotube array was grown electrochemically by using single and mixed electrolyte/s with 20 V constant potential at room temperature. Anodization was carried out for 120 min using five different electrolytes, e.g., H3PO4,NH4F, HF, NH4F with H3PO4and HF with H3PO4. Structural characterizations of the grown titania nanotubes were conducted by u...
Electrochemical anodization technique was employed to develop the wall-separated free standing ordered TiO2 nanotube array using the mixture of fluoride based electrolyte (e.g., NH4 F or HF) with another soft electrolyte (H3PO4). Anodization was carried out at room temperature, using a potential of 20 V, for 120 min using five different electrolyte...
Benzene, Toluene, and Xylene (BTX) are easily contaminating the environment through daily process, like motor and aircraft exhaust, petrol marketing, paintings etc., of modern age [1]. They are hazardous due to their carcinogenic nature and even at very low concentrations (ppb), long term exposure to BTX, may result in lymphatic and hematopoietic c...
In this paper we report on a Pd/TiO2/Si MIS (Metal-Insulator-Semiconductor) sensor for ethanol detection operating in the range of 100-250oC. The Sensing layer of TiO2 thin films were prepared through sol-gel method on a p-type Si wafer (with resistivity 2-5 Ωcm and <100> orientation) by dip coating technique. Titanium (IV) tetra Isopropoxide ((Ti...
In this present investigation, nanocrystalline TiO2 thin film (Thickness: ~1.04 µm) was prepared on p-Si (5 Ωcm, (100)) substrate by sol-gel technique using Titanium (IV) isopropoxide mixed with acetic acid and H2O maintaining bath temperature at 0ºC. After 10 hours of aging, film was deposited by dip coating method and annealed at 450ºC for 4 hour...
In this paper, we report on growth of electrochemically grown TiO2 nanotubes where the aspect ratio of nanotubes (length:diameter) was effectively controlled by the influence of mixed electrolytes. A weak
electrolyte, like ortho phosphoric acid when mixed with another strong electrolyte (hydro fluoric acid) was found to improve the aspect ratio of...
In this present investigation nanocrystalline TiO2 based sensor was developed for low ppm level (10-100) acetone detection. TiO2 thin film (Thickness: 1 μm) was prepared by solgel technique and deposited on the p-Si substrate (5 Ωcm, (100)) by dip coating method. Film was annealed at 450°C for 3 hours in air environment. XRD and FESEM study confirm...
Development of a highly repeatable multilevel resistive switching Au/TiO2/Ti memory device
is reported in this paper. Undoped rutile TiO2thin film, having a thickness of 480 nm, was
grown on high-purity Ti (99.5%) byin situthermal oxidation technique at 600
◦
C. Au metal
contact was used as a top electrode. The developed Au/TiO2/Ti memory device wa...
Thin film Sol-gel grown nano TiO2 based resistive sensor was developed to detect acetone at low temperature. Structural characterization were carried out using XRD, FESEM and AFM to ensure the crystalline, grain size and surface roughness of the TiO2 thin film and anatase phase TiO2 having particle size in order of 10 to 20 nm with average roughnes...
Questions
Question (1)
It is observed that the gas interaction with oxide nanoforms effectively changes the effective dielectric constant which is measurable in terms of capacitance change of the device. However, microwave transmission, reflection and absorption also are related to dielectric constant. But it is not clear that in which or what proportionate, these parameters (transmission, reflection and absorption) will change due to gas interaction. Is there any probability to absorb different frequency depending on different gas ambient? If it is, then what measures should be considered?
