Ongoing Project
1. Development of monolithic sensor platform for early diagnosis of lung cancer
2. Flexible transparent oxide material for thermoelectric material
3. Nanomaterial based sensors for air quality monitoring
PhD Thesis
Gas Sensor based on nano-structures of TiO2 : Influence of Dimensionality
Nanostructured semiconducting metal oxides have been slotted as the potential material for its applications in gas/vapor sensing systems. During the last couple of decades, extensive efforts have been devoted to reduce the sensor operating temperature, maximizing the parameters like response magnitude and minimizing the response time/recovery times. Nevertheless, the state of the art sensor device did not reach the commercial viability. The present work concerns about the improvement of the sensor parameters viz. operating temperature, response magnitude, response time/recovery time employing different dimensionality of TiO2 nanostructure for the detection of alcohol (methanol, ethanol and 2-propanol) and ketone (acetone and 2-butanone). The work was carried out by developing four different nanoforms of TiO2 viz., nanoparticle (0D), nanorod (1D), nanosheet (2D) and nanoflower (3D) synthesized through sol-gel technique (nanoparticle) and hydrothermal method (nanorod, nanosheet and nanoflower) at different precursor medium, temperature and pressure. All the nanoforms of TiO2 were characterized structurally, morphologically, optically and electrically. After detailed characterizations of all the nanoforms, four sensors employing zero dimensional (0D) nanoparticle, one dimensional (1D) nanorods, two dimensional (2D) nanosheets and three dimensional (3D) nanoflowers as the sensing layer, Pd as contact electrodes were fabricated for the efficient detection of alcohols (methanol, ethanol, 2-propanol) and ketones (acetone and 2-butanone). Sol gel derived undoped p- type (0D) TiO2 nanoparticle based sensor offered low ppm (0.5ppm) detection of methanol, ethanol, 2-propanol, acetone and 2-butanone with appreciable high response magnitude of ~45% (100°C), ~86% (200°C), ~44% (100°C), ~79% (150°C) and ~40% (150°C), respectively. On the other hand, one dimensional (1D) nanorod based sensor was developed with an aim to improve the response and recovery characteristics of the sensor (as one dimensional (1D) nanorod) exhibits the vertical electron transport property). The fastest response time and recovery time were found to be ~8/5s, ~6/6s, 5/4s, 6/12s and 8/19s towards methanol, ethanol, 2-propanol, acetone and 2-butanone detection, respectively. The operating temperature of the sensor was reduced by increasing the dimensionality of the nanostructure. The higher dimensional nanostructure like two dimensional (2D) nanosheets and three dimensional (3D) nanoflowers were also investigated in planner configuration. The developed two dimensional nanosheet offered promising sensing performance at relatively lower temperature of 100°C (towards methanol and ethanol) and 125°C (towards 2-propanol, acetone and 2-butanone). The operating temperature was even reduced to 90°C (for methanol and ethanol) and 60°C (2-propanol, acetone and 2-butanone) for the case of nanoflower based sensor. Sensing mechanism of the VOCs and resultant sensor response was correlated considering, Wolkenstein adsorption desorption isotherm and space charge model under the influence of alcohols and ketones.
The prime achievements of the present works are as follows:
M. Tech Thesis
Low Voltage Low Power Amplifier Design for Biomedical Signal Recording Application
In biomedical applications where a large output swing is required, the design of a low-noise and low power amplifier is critical. This thesis presents the design and simulation of a low noise low power amplifier for biomedical signal recording Application. Specifically, it is intended to be used in the front-end (FEA) of a Biomedical Electronics Detecting System Block and Electronics circuitry of general Biomedical Implanted Devices such as pacemaker.
B. Tech Major Project
Fast FPGA Based Pipelined Digit Serial /Parallel Multipliers for Fast Processor.
Throughout this project we focused on speed increment on different types of multiplier. A multiplier plays important role to a processor to be faster. So the system can be made faster by upgrading the multiplier .We started from a primitive unsigned serial/parallel multiplier and our motto was to upgrade it into a FPGA based pipelined digit serial/ parallel multiplier.
B. Tech Summer Project
Fabrication and Electrical characterizations of Schottky Diode
In this Project a schottky Diode has been fabricated in IC Manufacturing Lab and switching characteristics has observed. Also a comparison has carried out with simple diode in terms of switching characteristics. The ultimate goal of our research was to reduce the switching delay or increase the switching speed of schottky diode. Working in this laboratory I performed a number of fabrication steps, got acquainted with laboratory equipment and further studied V-I characteristics comparison with conventional Ohomic contact diode.