Jiten Dutta - Academia.edu (original) (raw)

Papers by Jiten Dutta

2012 International Conference on Devices, Circuits and Systems (ICDCS), 2012

A simple electronic circuit is proposed as an analog of the postsynaptic membrane of neuron. In t... more A simple electronic circuit is proposed as an analog of the postsynaptic membrane of neuron. In this circuit, the variable conductance of postsynaptic membrane of neuron dependence on the acetylcholine-receptor binding activity is represented by enzyme field effect transistor (ENFET) sensitive to acetylcholine. ENFET functions not only as a voltage controlled conductance but can also provide a means of measurement

4-Aminobutanoic acid (γ-aminobutyric acid, GABA) is the major inhibitory amino acid transmitter o... more 4-Aminobutanoic acid (γ-aminobutyric acid, GABA) is the major inhibitory amino acid transmitter of the mammalian central nervous system. It increases the chloride conductance of the neuronal membrane allowing chloride ions to flow down their electrochemical gradient into the cell. This influx of chloride ions into the cell produces inhibitory hyperpolarizing responses in neurons. The ion channels of post synaptic neuron depend on the transmitters diffused through the synaptic cleft and binds with the receptor sites. The binding with the receptor site is enzyme based. This analog of binding of neurotransmitters with the receptor sites of postsynaptic membrane which controls the conductance of Cl- ions is incorporated into the famous Hodgkin-Huxley (H-H) model of neuron to substitute the variable Cl- conductance. The activity of binding can be represented by enzyme modified field effect transistor (ENFET) sensitive to GABA. The ENFET is used as the circuit analog to simulate a group o...

2011 International Conference on Devices and Communications (ICDeCom), 2011

A simple electronic circuit is proposed to simulate bio- communication between neurons of our ner... more A simple electronic circuit is proposed to simulate bio- communication between neurons of our nervous system. In this model, the variable conductance of postsynaptic membrane of neuron dependence on the neurotransmitter-receptor binding activity is represented by ion sensitive field effect transistor (ISFET). ISFET is chosen as circuit analog because it has potential for on-chip circuit integration leading to the development

2012 2nd National Conference on Computational Intelligence and Signal Processing (CISP), 2012

Though the Hodgkin-Huxley (H-H) type models can reproduce electrophysiological measurements to a ... more Though the Hodgkin-Huxley (H-H) type models can reproduce electrophysiological measurements to a high degree of accuracy, its intrinsic complexity restricts its use in describing neural network dynamics. For this reason, many phenomenological spiking neuron models such as Integrate-and-Fire (I&F) models have been developed in the past to discuss aspects of neural coding, memory, or network dynamics. Due to replacement of the rich dynamics of H-H type models, I&F models can not correctly reproduce the neuronal dynamics close to the firing threshold. What is essential for a neuron to correctly reproduce the neural dynamics that it has to spend a significant amount of time far away from the firing threshold. We here discuss the development of a simple variant of Integrate-and-Fire model that can approximately reproduce the voltage dynamics of neuron analogous to H-H model. The model is simulated in ORCAD and results are compared both with H-H type and I&F models. It is seen that this I&F model can reproduce the neural dynamics as close as to H-H type models.

2017 International Conference on Computing, Communication and Automation (ICCCA)

This paper presents the effects of different dielectrics used as gate insulating material in the ... more This paper presents the effects of different dielectrics used as gate insulating material in the enzyme field effect transistor (ENFET) device. Different insulating materials have different properties which put an impact on the device sensitivity. The acid and base equilibrium of the dielectrics bring changes to the ENFET sensitivity. The pHpzc (pH at point of zero charge) is different for different dielectric material which also results in variations in the surface potential. The device model was tested for substrate sample with pH varying from 2 to 12. The potential variation that occurs at the surface of the device due to change in gate insulator was recorded and compared. It was found that with different gate insulating materials, the sensitivity of the device also varies. Ta2O5 was recorded as the most sensitive device under certain assumptions as compared to other insulating materials like SiO2, Al2O3, ZrO2, HfO2 and TiO2. The sensitivity variation with temperature is also shown for different materials.

IEEE Sensors Journal, Apr 15, 2018

2016 2nd International Conference on Advances in Electrical, Electronics, Information, Communication and Bio-Informatics (AEEICB)

Computation in neuron model plays a significant role in estimation of various parameters. In this... more Computation in neuron model plays a significant role in estimation of various parameters. In this paper, various parameters involved in Hodgkin-Huxley type model are estimated which were not explored earlier using evolutionary algorithm. Genetic algorithm is used to estimate the various parameter values associated with the activity of neuron and found to be better than other existing methods described in the paper. Estimation of parameter values is important for proper modeling of neuron that has importance in neurology for studying the receptor functions and electrical activity of membrane. Parameter values are estimated and compared with Hodgkin-Huxley's data.

2019 2nd International Conference on Innovations in Electronics, Signal Processing and Communication (IESC)

In this paper, a physical model for the drift behavior of carbon nanotube based ion sensitive fie... more In this paper, a physical model for the drift behavior of carbon nanotube based ion sensitive field effect transistor (CNTISFET) with high-κ dielectric material ZrO2 as gate oxide is presented. Drift has been modeled as the threshold voltage instability with time based on hopping transport mechanism, also known as the dispersive transport. The exposure of ZrO2 surface to electrolyte solution leads to chemical modification of the surface and the resultant capacitance of the insulator changes with time. Thus, the threshold voltage of the device varies with time. The model has been verified with experimental drift characteristic results and a good fit was obtained.

The past 40 years since the introduction of enzyme field-effect transistor (ENFET) in 1976 has be... more The past 40 years since the introduction of enzyme field-effect transistor (ENFET) in 1976 has been invaluable towards the development of biological sensors. Many devices came up with its own merits and demerits which made this area of research very popular worldwide. When the biological materials such as living organisms, cells, enzymes, DNA, etc., were combined with ISFET, BioFETs came up. By detailed study of the BioFETs one finds that most of the devices were formed of Si-based ISFETs. Though these devices have many advantages but when it came to sub 22 nm range, scaling problems arose which led to power dissipation, leakage, short channel effects, etc. To overcome these problems researchers opted for the use of carbon nanotubes (CNT) as channel material which gave better scalability, reduced power dissipation, better control over channel formation, etc. The complex fabrication process of the traditional Si-based devices was also simplified by introduction of junctionless CNTFET...

In this work, a high sensitivity BioFET has been fabricated and modeled for cholesterol detection... more In this work, a high sensitivity BioFET has been fabricated and modeled for cholesterol detection in serum samples. The device consists of indium tin oxide (ITO) coated glass as substrate, high κ-dielectric (ZrO2 ~ 25) as gate insulator, PEI-doped MWCNT as transporting layer and K/PPy/CNT nanocomposite as sensing membrane. Alkali metal potassium (K) and conducting polypyrrole have been used to enhance the conductivity and dispersion property of the nanocomposite in order to get better response time and detection limit. The layers have been deposited by electrochemical deposition and spin coating technique. The morphology and characteristics of the deposited layers were characterized using Fourier transform infrared spectroscopy (FTIR), field emission scanning microscopy (FESM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and cyclic voltammetry (CV). The modeling has been done using the enzymatic reactions between cholesterol substrate and cholesterol oxidase enzyme,...

2017 International Conference on Innovations in Electronics, Signal Processing and Communication (IESC), 2017

The gate oxide layer determines the sensitivity of an Ion Sensitive Field Effect Transistor(lSFET... more The gate oxide layer determines the sensitivity of an Ion Sensitive Field Effect Transistor(lSFET). The sensitivity of HfO2 and ZrO2, two high κ gate dielectric oxides have been determined theoretically by using Bousse's model and found to be equal to 56.3 mV/pH and 58.2 mV/pH respectively in the pH range 1–14. The effect of temperature on sensitivity was also theoretically obtained. The sensitivity reaches maximum value of 69.7 mV/pH and 71.1 mV/pH for HfO2 and ZrO2 in the temperature range 5–90 °C. Experiments then have been performed on carbon nanotube (CNT) based fabricated junctionless ISFET devices (CNTJLlSFET) and result shows a sensitivity of 57.5 mV/pH for HfO2 gate ISFET and 60 mV/pH for ZrO2 gate lSFET at room temperature. The experimental output characteristics relevant to CNT in the pH range 5–9 have been compared with that of theoretical results.

In this work, two important layers namely transporting and bio-sensitive layer of CNT-BioFET have... more In this work, two important layers namely transporting and bio-sensitive layer of CNT-BioFET have been fabricated for Creatinine detection using solution process. Creatinine is a waste product which is required for the detection of renal, muscle and thyroid function. For the fabrication of the BioFET, layers of CNT and ZrO2 have been deposited one after another to serve as transporting layer and oxide layer respectively. The oxide layer depositions and CNT nano-composite layer have been done using PGSTAT128 N and programmable spin coating system (spinNXG-P2H) respectively. The immobilization of enzyme (Creatinine Deiminase) can be done using silicalite as adsorbent by drop casting. The physical characterization of deposited layers was done by SEM (Scanning electron Microscope) and X-ray diffraction (XRD). The XRD results of the deposited layers show the characteristic peaks of the corresponding layer. SEM analysis show physical structure and dimensions of the deposited films. The si...

In this work, carbon nanotube based ENFET for cholesterol detection has been developed. The fabri... more In this work, carbon nanotube based ENFET for cholesterol detection has been developed. The fabricated device replaces silicon substrate with PEI doped carbon nanotube which offers high carrier mobility, excellent stability and enhanced sensitivity. The device is fabricated on indium tin oxide glass substrate. Zirconia (ZrO2) having high dielectric constant is used as top and bottom gate insulator. PPy/K/CNT nanocomposite serves as the sensing layer for the cholesterol ENFET. Cholesterol oxidase (ChOx) is immobilized covalently on the sensing layer for detection of cholesterol. Carbon nanotube composites with conductive polymers offer fast electron transfer kinetics between reaction sites and the active binding sites. Moreover, polypyrrole also works as a support matrix for enzyme immobilization. The fabricated device has been characterized for detection of cholesterol (0.5-24 mM). Electrical response has been recorded using (Scientific SM 7023) multimeter in the presence of phospha...

2019 6th International Conference on Signal Processing and Integrated Networks (SPIN)

This work explores the feasibility of electrochemical deposition (ECD) of zirconia on ITO coated ... more This work explores the feasibility of electrochemical deposition (ECD) of zirconia on ITO coated glass. Zirconia is deposited as bottom insulating layer and gate oxide layer for fabrication of a high sensitivity CNT based cholesterol ENFET. The thickness and morphology of the zirconia layers are very much affected by the process conditions such as temperature, working electrode potential, current density, deposition time and properties of the solvent. The effect of these factors on the quality of the layers formed has been considered in detail in this paper. Zirconia films (ZrO2) of different thickness have been deposited electrochemically on ITO coated glass. Experiments have been carried out in aqueous and non-aqueous electrolyte solution of zirconium tetra chloride (ZrCl4) at different temperatures. The thickness of the deposited layers varied within the range of 35–256 nm. The formation of stoichiometric layer of ZrO2 has been confirmed by X-ray diffraction and SEM results.

We have reported a high-performance dual gated carbon nanotube enzyme modified field-effect trans... more We have reported a high-performance dual gated carbon nanotube enzyme modified field-effect transistor (CNT-ENFET) for cholesterol detection. To improve the device performance, we have used dual-gate design with high κ dielectric as top gate and low κ dielectric as bottom gate and a nanocomposite of potassium doped carbon nanotube with polypyrrole (K/PPy/CNT) as the biosensing membrane. The device exhibited a good sensitivity (~1.0 V/decade), low response time (~1 s), wide dynamic range (0.1 - 25) mM, wide linear range (2-20 mM), low detection limit (0.11 mM), good stability (7 months) and high selectivity (interference ~1.8 %).

Materials Today: Proceedings

Abstract Highly Sensitive Potassium-Doped Polypyrrole/Carbon Nanotube (K/PPy/CNT) - based Enzyme ... more Abstract Highly Sensitive Potassium-Doped Polypyrrole/Carbon Nanotube (K/PPy/CNT) - based Enzyme Field Effect Transistor (ENFET) has been modelled for Cholesterol Detection. The device consists of P-type graphene as substrate, N-type graphene as source and drain regions, ZrO 2 as gate insulator and K/PPy/CNT composite as sensing membrane on the top of ZrO 2 layer. The modelling is done using the enzymatic reactions of the enzyme cholesterol oxidase on cholesterol substrate, diffusion phenomena of the main substrate (i.e. cholesterol) in phosphate buffer saline (PBS) as electrolyte, acid/base reactions of the product (H 2 O 2 ) in the PBS solution (pH=7) and the pH detection properties of ISFET. The thickness of the enzyme layer here is in nm range which is very less compared to other ENFETs whose thickness is in μm range. The use of K doped CNT as sensing membrane has increased the sensitivity of the device at normal temperature and pH. As a result of this increased sensitivity, variations of the substrate and product concentrations are noticed even at nanometer range of the enzyme layer which results in change in pH of the ISFET. The potential variation with change in pH is depicted by the model given by Bousse. A good fit is obtained between the modelling and experimental results

International Journal of Numerical Modelling: Electronic Networks, Devices and Fields

IEEE Sensors Journal

We have reported the fabrication and characterization of dual-gate (high-<inline-formula> &... more We have reported the fabrication and characterization of dual-gate (high-<inline-formula> <tex-math notation="LaTeX">$\kappa $ </tex-math></inline-formula> as top gate and low-<inline-formula> <tex-math notation="LaTeX">$\kappa $ </tex-math></inline-formula> as bottom gate dielectrics) carbon nanotube (CNT) ion-sensitive field effect transistor (DG-CNTISFET) for detection of pH of electrolyte. To improve the sensing performance beyond the Nernstian sensitivity limit of 59 mV/pH at room temperature (25° C), HfO₂ (<inline-formula> <tex-math notation="LaTeX">$\kappa \sim 25$ </tex-math></inline-formula>) has been used as a top gate dielectric and ZnO (<inline-formula> <tex-math notation="LaTeX">$\kappa \sim 1.5$ </tex-math></inline-formula>) as a bottom gate dielectric. The device has been fabricated by chemical solution process (using AUTOLAB Potentiostat/Galvanostat PGSTAT128N system) and characterized in electrolyte solutions of range 5–9 pH. In this range of pH, the device has shown a good linearity and an improved sensitivity of 943 mV/pH at room temperature. The device showed the drift rate of 13.5 mV/pH at pH 7 and the hysteresis width of 15.8 mV in a pH loop of <inline-formula> <tex-math notation="LaTeX">${7\to 9\to 7\to 5\to 7.}$ </tex-math></inline-formula> These suppressed non-ideal effects of the device along with the high sensitivity are suitable for nanobiosensing applications.

International Journal of Information Technology

In this paper a reusable, generalized, parallel DNA computing model is presented to evaluate any ... more In this paper a reusable, generalized, parallel DNA computing model is presented to evaluate any logic function at molecular level. The gate strands designed by this algorithm act both as logic operator and sensor to detect the output. Though this model could be employed to simulate vast range of logic functions but for simplicity of explanation theoretical simulation results of DNA based NAND, NOR, half-adder, full-adder and four-bit carry ripple adder are demonstrated to validate this model. The proposed model relies on the induced hairpin formation property of naphthyridine dimer in a G–G mismatched DNA oligo strand which is integrated with a generalized gate design algorithm. Contribution of this work lies in the inclusion of features like single design strategy for any logic function, uniformity in representation of logic 0 and 1 throughout the simulation process and is cost and implementation effective with parallel processing capacity.

International Journal of Numerical Modelling: Electronic Networks, Devices and Fields

Potassium-doped polypyrrole/carbon nanotube (K/PPy/CNT)–based graphene enzyme field-effect transi... more Potassium-doped polypyrrole/carbon nanotube (K/PPy/CNT)–based graphene enzyme field-effect transistor has been modeled for cholesterol detection. The device consists of boron-doped p-type graphene as substrate, nitrogen-doped n-type graphene as source and drain regions, high-κ dielectric ZrO2 as gate insulator, and K/PPy/CNT composite as sensing membrane on the top of ZrO2 layer. The modeling is done using the enzymatic reactions of the enzyme cholesterol oxidase on cholesterol substrate, diffusion phenomena of the main substrate (ie, cholesterol) in phosphate buffer saline, acid/base reactions of the product (H2O2) in the phosphate buffer saline solution (pH = 7), and the pH detection properties of ion sensitive field effect transistor. The thickness of the enzyme layer here is in nanometer range, which is very less compared to other enzyme field-effect transistors whose thickness is in micrometer range. The use of K-doped CNT as sensing membrane has increased the sensitivity of the device at normal temperature and pH. As a result of this increased sensitivity, variations of the substrate and product concentrations are noticed even at nanometer range of the enzyme layer, which results in change in pH of the ion sensitive field effect transistor. A good fit is obtained between the modeling and experimental results.

2012 International Conference on Devices, Circuits and Systems (ICDCS), 2012

A simple electronic circuit is proposed as an analog of the postsynaptic membrane of neuron. In t... more A simple electronic circuit is proposed as an analog of the postsynaptic membrane of neuron. In this circuit, the variable conductance of postsynaptic membrane of neuron dependence on the acetylcholine-receptor binding activity is represented by enzyme field effect transistor (ENFET) sensitive to acetylcholine. ENFET functions not only as a voltage controlled conductance but can also provide a means of measurement

4-Aminobutanoic acid (γ-aminobutyric acid, GABA) is the major inhibitory amino acid transmitter o... more 4-Aminobutanoic acid (γ-aminobutyric acid, GABA) is the major inhibitory amino acid transmitter of the mammalian central nervous system. It increases the chloride conductance of the neuronal membrane allowing chloride ions to flow down their electrochemical gradient into the cell. This influx of chloride ions into the cell produces inhibitory hyperpolarizing responses in neurons. The ion channels of post synaptic neuron depend on the transmitters diffused through the synaptic cleft and binds with the receptor sites. The binding with the receptor site is enzyme based. This analog of binding of neurotransmitters with the receptor sites of postsynaptic membrane which controls the conductance of Cl- ions is incorporated into the famous Hodgkin-Huxley (H-H) model of neuron to substitute the variable Cl- conductance. The activity of binding can be represented by enzyme modified field effect transistor (ENFET) sensitive to GABA. The ENFET is used as the circuit analog to simulate a group o...

2011 International Conference on Devices and Communications (ICDeCom), 2011

A simple electronic circuit is proposed to simulate bio- communication between neurons of our ner... more A simple electronic circuit is proposed to simulate bio- communication between neurons of our nervous system. In this model, the variable conductance of postsynaptic membrane of neuron dependence on the neurotransmitter-receptor binding activity is represented by ion sensitive field effect transistor (ISFET). ISFET is chosen as circuit analog because it has potential for on-chip circuit integration leading to the development

2012 2nd National Conference on Computational Intelligence and Signal Processing (CISP), 2012

Though the Hodgkin-Huxley (H-H) type models can reproduce electrophysiological measurements to a ... more Though the Hodgkin-Huxley (H-H) type models can reproduce electrophysiological measurements to a high degree of accuracy, its intrinsic complexity restricts its use in describing neural network dynamics. For this reason, many phenomenological spiking neuron models such as Integrate-and-Fire (I&F) models have been developed in the past to discuss aspects of neural coding, memory, or network dynamics. Due to replacement of the rich dynamics of H-H type models, I&F models can not correctly reproduce the neuronal dynamics close to the firing threshold. What is essential for a neuron to correctly reproduce the neural dynamics that it has to spend a significant amount of time far away from the firing threshold. We here discuss the development of a simple variant of Integrate-and-Fire model that can approximately reproduce the voltage dynamics of neuron analogous to H-H model. The model is simulated in ORCAD and results are compared both with H-H type and I&F models. It is seen that this I&F model can reproduce the neural dynamics as close as to H-H type models.

2017 International Conference on Computing, Communication and Automation (ICCCA)

This paper presents the effects of different dielectrics used as gate insulating material in the ... more This paper presents the effects of different dielectrics used as gate insulating material in the enzyme field effect transistor (ENFET) device. Different insulating materials have different properties which put an impact on the device sensitivity. The acid and base equilibrium of the dielectrics bring changes to the ENFET sensitivity. The pHpzc (pH at point of zero charge) is different for different dielectric material which also results in variations in the surface potential. The device model was tested for substrate sample with pH varying from 2 to 12. The potential variation that occurs at the surface of the device due to change in gate insulator was recorded and compared. It was found that with different gate insulating materials, the sensitivity of the device also varies. Ta2O5 was recorded as the most sensitive device under certain assumptions as compared to other insulating materials like SiO2, Al2O3, ZrO2, HfO2 and TiO2. The sensitivity variation with temperature is also shown for different materials.

IEEE Sensors Journal, Apr 15, 2018

2016 2nd International Conference on Advances in Electrical, Electronics, Information, Communication and Bio-Informatics (AEEICB)

Computation in neuron model plays a significant role in estimation of various parameters. In this... more Computation in neuron model plays a significant role in estimation of various parameters. In this paper, various parameters involved in Hodgkin-Huxley type model are estimated which were not explored earlier using evolutionary algorithm. Genetic algorithm is used to estimate the various parameter values associated with the activity of neuron and found to be better than other existing methods described in the paper. Estimation of parameter values is important for proper modeling of neuron that has importance in neurology for studying the receptor functions and electrical activity of membrane. Parameter values are estimated and compared with Hodgkin-Huxley's data.

2019 2nd International Conference on Innovations in Electronics, Signal Processing and Communication (IESC)

In this paper, a physical model for the drift behavior of carbon nanotube based ion sensitive fie... more In this paper, a physical model for the drift behavior of carbon nanotube based ion sensitive field effect transistor (CNTISFET) with high-κ dielectric material ZrO2 as gate oxide is presented. Drift has been modeled as the threshold voltage instability with time based on hopping transport mechanism, also known as the dispersive transport. The exposure of ZrO2 surface to electrolyte solution leads to chemical modification of the surface and the resultant capacitance of the insulator changes with time. Thus, the threshold voltage of the device varies with time. The model has been verified with experimental drift characteristic results and a good fit was obtained.

The past 40 years since the introduction of enzyme field-effect transistor (ENFET) in 1976 has be... more The past 40 years since the introduction of enzyme field-effect transistor (ENFET) in 1976 has been invaluable towards the development of biological sensors. Many devices came up with its own merits and demerits which made this area of research very popular worldwide. When the biological materials such as living organisms, cells, enzymes, DNA, etc., were combined with ISFET, BioFETs came up. By detailed study of the BioFETs one finds that most of the devices were formed of Si-based ISFETs. Though these devices have many advantages but when it came to sub 22 nm range, scaling problems arose which led to power dissipation, leakage, short channel effects, etc. To overcome these problems researchers opted for the use of carbon nanotubes (CNT) as channel material which gave better scalability, reduced power dissipation, better control over channel formation, etc. The complex fabrication process of the traditional Si-based devices was also simplified by introduction of junctionless CNTFET...

In this work, a high sensitivity BioFET has been fabricated and modeled for cholesterol detection... more In this work, a high sensitivity BioFET has been fabricated and modeled for cholesterol detection in serum samples. The device consists of indium tin oxide (ITO) coated glass as substrate, high κ-dielectric (ZrO2 ~ 25) as gate insulator, PEI-doped MWCNT as transporting layer and K/PPy/CNT nanocomposite as sensing membrane. Alkali metal potassium (K) and conducting polypyrrole have been used to enhance the conductivity and dispersion property of the nanocomposite in order to get better response time and detection limit. The layers have been deposited by electrochemical deposition and spin coating technique. The morphology and characteristics of the deposited layers were characterized using Fourier transform infrared spectroscopy (FTIR), field emission scanning microscopy (FESM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and cyclic voltammetry (CV). The modeling has been done using the enzymatic reactions between cholesterol substrate and cholesterol oxidase enzyme,...

2017 International Conference on Innovations in Electronics, Signal Processing and Communication (IESC), 2017

The gate oxide layer determines the sensitivity of an Ion Sensitive Field Effect Transistor(lSFET... more The gate oxide layer determines the sensitivity of an Ion Sensitive Field Effect Transistor(lSFET). The sensitivity of HfO2 and ZrO2, two high κ gate dielectric oxides have been determined theoretically by using Bousse's model and found to be equal to 56.3 mV/pH and 58.2 mV/pH respectively in the pH range 1–14. The effect of temperature on sensitivity was also theoretically obtained. The sensitivity reaches maximum value of 69.7 mV/pH and 71.1 mV/pH for HfO2 and ZrO2 in the temperature range 5–90 °C. Experiments then have been performed on carbon nanotube (CNT) based fabricated junctionless ISFET devices (CNTJLlSFET) and result shows a sensitivity of 57.5 mV/pH for HfO2 gate ISFET and 60 mV/pH for ZrO2 gate lSFET at room temperature. The experimental output characteristics relevant to CNT in the pH range 5–9 have been compared with that of theoretical results.

In this work, two important layers namely transporting and bio-sensitive layer of CNT-BioFET have... more In this work, two important layers namely transporting and bio-sensitive layer of CNT-BioFET have been fabricated for Creatinine detection using solution process. Creatinine is a waste product which is required for the detection of renal, muscle and thyroid function. For the fabrication of the BioFET, layers of CNT and ZrO2 have been deposited one after another to serve as transporting layer and oxide layer respectively. The oxide layer depositions and CNT nano-composite layer have been done using PGSTAT128 N and programmable spin coating system (spinNXG-P2H) respectively. The immobilization of enzyme (Creatinine Deiminase) can be done using silicalite as adsorbent by drop casting. The physical characterization of deposited layers was done by SEM (Scanning electron Microscope) and X-ray diffraction (XRD). The XRD results of the deposited layers show the characteristic peaks of the corresponding layer. SEM analysis show physical structure and dimensions of the deposited films. The si...

In this work, carbon nanotube based ENFET for cholesterol detection has been developed. The fabri... more In this work, carbon nanotube based ENFET for cholesterol detection has been developed. The fabricated device replaces silicon substrate with PEI doped carbon nanotube which offers high carrier mobility, excellent stability and enhanced sensitivity. The device is fabricated on indium tin oxide glass substrate. Zirconia (ZrO2) having high dielectric constant is used as top and bottom gate insulator. PPy/K/CNT nanocomposite serves as the sensing layer for the cholesterol ENFET. Cholesterol oxidase (ChOx) is immobilized covalently on the sensing layer for detection of cholesterol. Carbon nanotube composites with conductive polymers offer fast electron transfer kinetics between reaction sites and the active binding sites. Moreover, polypyrrole also works as a support matrix for enzyme immobilization. The fabricated device has been characterized for detection of cholesterol (0.5-24 mM). Electrical response has been recorded using (Scientific SM 7023) multimeter in the presence of phospha...

2019 6th International Conference on Signal Processing and Integrated Networks (SPIN)

This work explores the feasibility of electrochemical deposition (ECD) of zirconia on ITO coated ... more This work explores the feasibility of electrochemical deposition (ECD) of zirconia on ITO coated glass. Zirconia is deposited as bottom insulating layer and gate oxide layer for fabrication of a high sensitivity CNT based cholesterol ENFET. The thickness and morphology of the zirconia layers are very much affected by the process conditions such as temperature, working electrode potential, current density, deposition time and properties of the solvent. The effect of these factors on the quality of the layers formed has been considered in detail in this paper. Zirconia films (ZrO2) of different thickness have been deposited electrochemically on ITO coated glass. Experiments have been carried out in aqueous and non-aqueous electrolyte solution of zirconium tetra chloride (ZrCl4) at different temperatures. The thickness of the deposited layers varied within the range of 35–256 nm. The formation of stoichiometric layer of ZrO2 has been confirmed by X-ray diffraction and SEM results.

We have reported a high-performance dual gated carbon nanotube enzyme modified field-effect trans... more We have reported a high-performance dual gated carbon nanotube enzyme modified field-effect transistor (CNT-ENFET) for cholesterol detection. To improve the device performance, we have used dual-gate design with high κ dielectric as top gate and low κ dielectric as bottom gate and a nanocomposite of potassium doped carbon nanotube with polypyrrole (K/PPy/CNT) as the biosensing membrane. The device exhibited a good sensitivity (~1.0 V/decade), low response time (~1 s), wide dynamic range (0.1 - 25) mM, wide linear range (2-20 mM), low detection limit (0.11 mM), good stability (7 months) and high selectivity (interference ~1.8 %).

Materials Today: Proceedings

Abstract Highly Sensitive Potassium-Doped Polypyrrole/Carbon Nanotube (K/PPy/CNT) - based Enzyme ... more Abstract Highly Sensitive Potassium-Doped Polypyrrole/Carbon Nanotube (K/PPy/CNT) - based Enzyme Field Effect Transistor (ENFET) has been modelled for Cholesterol Detection. The device consists of P-type graphene as substrate, N-type graphene as source and drain regions, ZrO 2 as gate insulator and K/PPy/CNT composite as sensing membrane on the top of ZrO 2 layer. The modelling is done using the enzymatic reactions of the enzyme cholesterol oxidase on cholesterol substrate, diffusion phenomena of the main substrate (i.e. cholesterol) in phosphate buffer saline (PBS) as electrolyte, acid/base reactions of the product (H 2 O 2 ) in the PBS solution (pH=7) and the pH detection properties of ISFET. The thickness of the enzyme layer here is in nm range which is very less compared to other ENFETs whose thickness is in μm range. The use of K doped CNT as sensing membrane has increased the sensitivity of the device at normal temperature and pH. As a result of this increased sensitivity, variations of the substrate and product concentrations are noticed even at nanometer range of the enzyme layer which results in change in pH of the ISFET. The potential variation with change in pH is depicted by the model given by Bousse. A good fit is obtained between the modelling and experimental results

International Journal of Numerical Modelling: Electronic Networks, Devices and Fields

IEEE Sensors Journal

We have reported the fabrication and characterization of dual-gate (high-<inline-formula> &... more We have reported the fabrication and characterization of dual-gate (high-<inline-formula> <tex-math notation="LaTeX">$\kappa $ </tex-math></inline-formula> as top gate and low-<inline-formula> <tex-math notation="LaTeX">$\kappa $ </tex-math></inline-formula> as bottom gate dielectrics) carbon nanotube (CNT) ion-sensitive field effect transistor (DG-CNTISFET) for detection of pH of electrolyte. To improve the sensing performance beyond the Nernstian sensitivity limit of 59 mV/pH at room temperature (25° C), HfO₂ (<inline-formula> <tex-math notation="LaTeX">$\kappa \sim 25$ </tex-math></inline-formula>) has been used as a top gate dielectric and ZnO (<inline-formula> <tex-math notation="LaTeX">$\kappa \sim 1.5$ </tex-math></inline-formula>) as a bottom gate dielectric. The device has been fabricated by chemical solution process (using AUTOLAB Potentiostat/Galvanostat PGSTAT128N system) and characterized in electrolyte solutions of range 5–9 pH. In this range of pH, the device has shown a good linearity and an improved sensitivity of 943 mV/pH at room temperature. The device showed the drift rate of 13.5 mV/pH at pH 7 and the hysteresis width of 15.8 mV in a pH loop of <inline-formula> <tex-math notation="LaTeX">${7\to 9\to 7\to 5\to 7.}$ </tex-math></inline-formula> These suppressed non-ideal effects of the device along with the high sensitivity are suitable for nanobiosensing applications.

International Journal of Information Technology

In this paper a reusable, generalized, parallel DNA computing model is presented to evaluate any ... more In this paper a reusable, generalized, parallel DNA computing model is presented to evaluate any logic function at molecular level. The gate strands designed by this algorithm act both as logic operator and sensor to detect the output. Though this model could be employed to simulate vast range of logic functions but for simplicity of explanation theoretical simulation results of DNA based NAND, NOR, half-adder, full-adder and four-bit carry ripple adder are demonstrated to validate this model. The proposed model relies on the induced hairpin formation property of naphthyridine dimer in a G–G mismatched DNA oligo strand which is integrated with a generalized gate design algorithm. Contribution of this work lies in the inclusion of features like single design strategy for any logic function, uniformity in representation of logic 0 and 1 throughout the simulation process and is cost and implementation effective with parallel processing capacity.

International Journal of Numerical Modelling: Electronic Networks, Devices and Fields

Potassium-doped polypyrrole/carbon nanotube (K/PPy/CNT)–based graphene enzyme field-effect transi... more Potassium-doped polypyrrole/carbon nanotube (K/PPy/CNT)–based graphene enzyme field-effect transistor has been modeled for cholesterol detection. The device consists of boron-doped p-type graphene as substrate, nitrogen-doped n-type graphene as source and drain regions, high-κ dielectric ZrO2 as gate insulator, and K/PPy/CNT composite as sensing membrane on the top of ZrO2 layer. The modeling is done using the enzymatic reactions of the enzyme cholesterol oxidase on cholesterol substrate, diffusion phenomena of the main substrate (ie, cholesterol) in phosphate buffer saline, acid/base reactions of the product (H2O2) in the phosphate buffer saline solution (pH = 7), and the pH detection properties of ion sensitive field effect transistor. The thickness of the enzyme layer here is in nanometer range, which is very less compared to other enzyme field-effect transistors whose thickness is in micrometer range. The use of K-doped CNT as sensing membrane has increased the sensitivity of the device at normal temperature and pH. As a result of this increased sensitivity, variations of the substrate and product concentrations are noticed even at nanometer range of the enzyme layer, which results in change in pH of the ion sensitive field effect transistor. A good fit is obtained between the modeling and experimental results.