Pramod Kumar Tiwari

Bio: Pramod Kumar Tiwari is an academic researcher from Indian Institute of Technology Patna. The author has contributed to research in topics: MOSFET & Subthreshold conduction. The author has an hindex of 18, co-authored 125 publications receiving 968 citations. Previous affiliations of Pramod Kumar Tiwari include Jiwaji University & National Institute of Technology, Rourkela.

A two-dimensional analytical model for threshold voltage of short-channel triple-material double-gate metal-oxide-semiconductor field-effect transistors

Abstract: A two-dimensional (2D) analytical model for the threshold voltage of fully depleted short-channel triple-material double-gate (DG) metal-oxide-semiconductor field-effect transistors (MOSFETs) is presented in this paper. The 2D Poisson’s equation has been solved with suitable boundary conditions by applying the parabolic potential approximation. The lightly doped channel has been taken to enhance the device performance in terms of higher carrier mobility and minimum dopant fluctuation. The improved hot carrier effects over the double-material DG MOSFETs have been demonstrated. Different length ratios of three channel regions related to different gate materials have been optimized to minimize short-channel effects. The effects of device parameters on the threshold voltage have also been discussed. The model results have been compared with the simulation data obtained by using the commercially available device simulation software ATLAS™.

A two-dimensional model for the potential distribution and threshold voltage of short-channel double-gate metal-oxide-semiconductor field-effect transistors with a vertical Gaussian-like doping profile

Abstract: A two-dimensional (2D) model for the threshold voltage of the short-channel double-gate (DG) metal-oxide-semiconductor field-effect transistors (MOSFETs) with a vertical Gaussian-like doping profile is proposed in this paper. The evanescent mode analysis has been used to solve the 2D Poisson’s equation to obtain the channel potential function of the device. The minimum surface potential has been used to model the threshold voltage of the DG MOSFETs. Threshold voltage variations against channel length for different device parameters have been demonstrated. The validity of the proposed model is shown by comparing the results with the numerical simulation data obtained by using the commercially available ATLAS™, a 2D device simulator from SILVACO.

An Analytical Threshold Voltage Model for Triple-Material Cylindrical Gate-All-Around (TM-CGAA) MOSFETs

Abstract: In this paper, an analytical threshold voltage model is proposed for a triple-material cylindrical gate-all-around MOSFET considering parabolic approximation of the potential along the radial axis. The center (axial) and the surface potential models are obtained by solving the 2-D Poisson's equation in the cylindrical coordinate system. This paper refutes the estimation of the natural length using surface potential as in previous work and proposes the use of center-potential-based natural length formulation for an accurate subthreshold analysis. The developed center potential model is used further to formulate the threshold voltage model and also extract drain-induced barrier lowering (DIBL) from the same. The effects of the device parameters like the cylinder diameter, oxide thickness, gate length ratio, etc., on the threshold voltage and DIBL are also studied in this paper. The model is verified by the simulations obtained from 3D numerical device simulator Sentaurus from Synopsys.

Simulation Study of Dielectric Modulated Dual Channel Trench Gate TFET-Based Biosensor

Abstract: A dielectric modulated dual channel trench gate tunnel FET (DM-DCTGTFET) based biosensor is proposed for label-free detection of biomolecules. The gate of DM-DCTGTFET is placed vertically in a trench for creating two channels on both sides of the gate. The parallel conduction of two channels enhances the current of the DM-DCTGTFET. Further, in the proposed structure, two cavities are carved in the gate-oxide on either side of gate for biomolecules immobilization. The sensitivity performance of DM-DCTGTFET is analyzed using 2D simulations in the TCAD tool (ATLAS). The proposed structure exhibits high current sensitivity (~1012) as well as exorbitant voltage sensitivity ( $5.2 {V}$ ) which are significantly higher than the recently reported TFET based biosensors. Therefore, the DM-DCTGTFET biosensor is a highly promising structure due to dual sensing capabilities for biomolecules.

A 2D analytical model of the channel potential and threshold voltage of Double-Gate (DG) MOSFETs with vertical Gaussian doping profile

Abstract: The paper presents a 2D analytical model for the potential function and threshold voltage of symmetric Double-Gate (DG) MOSFETs with vertical Gaussian doping profile in the channel.

Gallbladder cancer epidemiology, pathogenesis and molecular genetics: Recent update.

Abstract: Gallbladder cancer is a malignancy of biliary tract which is infrequent in developed countries but common in some specific geographical regions of developing countries. Late diagnosis and deprived prognosis are major problems for treatment of gallbladder carcinoma. The dramatic associations of this orphan cancer with various genetic and environmental factors are responsible for its poorly defined pathogenesis. An understanding to the relationship between epidemiology, molecular genetics and pathogenesis of gallbladder cancer can add new insights to its undetermined pathophysiology. Present review article provides a recent update regarding epidemiology, pathogenesis, and molecular genetics of gallbladder cancer. We systematically reviewed published literature on gallbladder cancer from online search engine PubMed (http://www.ncbi.nlm.nih.gov/pubmed). Various keywords used for retrieval of articles were Gallbladder, cancer Epidemiology, molecular genetics and bullion operators like AND, OR, NOT. Cross references were manually searched from various online search engines (http://www.ncbi.nlm.nih.gov/pubmed,https://scholar.google.co.in/, http://www.medline.com/home.jsp). Most of the articles published from 1982 to 2015 in peer reviewed journals have been included in this review.

Phycoremediation of wastewaters: a synergistic approach using microalgae for bioremediation and biomass generation

Abstract: Discharge of untreated domestic and industrial wastewater into aquatic bodies is posing a serious eutrophication threat, leading to a slow degradation of the water resources. A number of physical, chemical and biological methods have been developed for the treatment of wastewaters; among these, the use of microalgae is considered as a more eco-friendly and economical approaches. Microalgae are versatile organisms which perform multiple roles in the environment—bioremediation of wastewater, gleaning of excess nutrients and in turn, generate valuable biomass which finds applications in the food, biofuel and pharmaceutical industries. They are currently being utilized to reduce the high nutrient load (especially N and P) from wastewaters, which fulfill the growth requirements of microalgae, making it a suitable cultivation medium for biomass production. The present review represents a comprehensive compilation of reports on microalgal diversity of wastewaters, followed by a critical overview of their utilization, suitability and potential in bioremediation vis-a-vis biomass production. This review also emphasizes the superiority of polyalgal and consortial approaches in wastewater treatment, as compared to the use of unialgal inocula, besides providing useful pointers for future research needs in this area.