Research Publications

Shubham Rahi, Rajender Kumar, Sapna Singh, Prasanna Misra, Ganesh C. Patil, Trupti Ranjan Lenka, Ankur Solanki, Anurag Chauhan, Balwinder Raj, Pinku Nath, Sudhanshu Choudhary, "Graphene-boron nitride-transition metal dichalcogenides heterostructure based MISFET", Micro and Nanostructures, Volume 208, 2025, 208320, ISSN 2773-0123, doi: https://doi.org/10.1016/j.micrna.2025.208320.  (IMPACT FACTOR: 3.0)
Abstract: Stacking of 2D materials has opened new dimensions in the area of Nano-electronics as both optical and electronic properties of the material change significantly by altering number of layers stacked and materials stacked. A vander waal's (vdWH) heterostructure based metal insulator semiconductor field effect transistor (MISFET) with various channel materials like MoS2, MoSe2 and WS2 is investigated to assess the differences in electronic properties at both material and device levels. The results suggest that amongst all transition metal dichalcogenides (TMDs) channel materials considered, WS2 has lowest effective mass (for both electron and hole) and highest Idsat (saturation current) ∼9.216 × 10−5 Å/ μ m which suggests the use of WS2 in making high performance Field Effect Transistors. However, because bulk WS2 is an indirect bandgap material, it is unsuitable for the fabrication of optical devices. This limitation is addressed by using monolayer WS2, which possesses a direct bandgap. The values of Idsat for MoS2 and MoSe2 based devices are obtained as ∼4.37 × 10−5 A/ μ m and ∼2.323 × 10−5 A/ μ m. Furthermore, WS2 as channel material has lowest threshold voltage ∼1 V in comparison to ∼1.1 V and ∼1.2 V for MoS2 and MoSe2 based transistors.

Savera Yadav, Rajender Kumar, Sapna Singh, Prasanna Misra, Ganesh C. Patil, Trupti Ranjan Lenka, Ankur Solanki, Anurag Chauhan, Sudhanshu Choudhary, Electronic and optical properties of Ca2TiSi(O1-xSx)6 and it′s alloys for use in solar cell application, J. Nanophoton. 19(3), 036001 (2025), doi: 10.1117/1.JNP.19.036001.  (IMPACT FACTOR: 1.1)
Abstract: The electronic and optical properties of cubic and triclinic structures of Ca2TiSiO6 and its new alloys Ca2TiSi(O1-xSx)6  are investigated. The method of research is a computational investigation using density functional theory. The results suggest that alloys of triclinic structure Ca2TiSi(O1-xSx)6 are suitable and cubic structure is not suitable for optoelectronics applications as alloys of cubic structure result in indirect bandgap. Substitution of sulfur (S) in place of oxygen (O) using a partial element mixing approach results in large tunability in the optical and electronic properties of the new alloy. Bandgap is tuned in the range of 1.5 to 0.97 eV by varying O and S percentages in the alloys Ca2TiSi(O0.92S0.08)6, Ca2TiSi(O0.8S0.2)6, and Ca2TiSi(O0.65S0.35)6. A significant increase in optical absorption is obtained in the visible region for these new alloys in comparison to the pristine triclinic structure. The highest absorption is obtained in Ca2TiSi(O0.8S0.2)6 alloy as its bandgap of ∼1.21 eV is near the Shockley–Queisser limit of ∼1.34 eV. The refractive index and dielectric constant are also calculated, where the peaks are in agreement with the trends in absorption peaks. High absorption in the visible region and bandgap tun- ability in these alloys could make them useful for solar cells and other optoelectronic applications.

A. Chauhan, K. Sharma, and S. Choudhary, “Transition metal induced- magnetization and spin-polarisation in black arsenic phosphorous,” Ain Shams Eng. J., p. 102632, 2024, doi:https://doi.org/10.1016/j.asej.2024.102632. (IMPACT FACTOR: 6.0)
Abstract : The electronic and magnetic properties of two-dimensional black Arsenic Phosphorus (b-AsP) on adsorption of Transition Metals (TM) on its surface are investigated using density functional theory (DFT) based on first principles calculations. Spin-density of states (S-DOS) and the bandstructure of all the transition metals adsorbed structures have been plotted which reveals their change from non-magnetic to magnetic behaviour. The results suggest that pristine b-AsP which is a non-magnetic semiconductor turns into a half metal ferromagnet (HMF) on adsorption of Co, Fe and Ti, and it turns into a ferromagnet (FM) on adsorption of Cr and Zr. The total magnetic moments were also calculated to further support our results and findings. Strong magnetic moments were observed for Cr, Fe and Ti adsorbed b-AsP structures. Ag, Cu and Mo adsorption over b-AsP results into non-magnetic metallic characteristics with very weak magnetic moments. This transformation from a non-magnetic semiconductor to a magnetic HMF or FM material demonstrates the potential use of b-AsP in designing spin magnetic devices for various spin-based applications.

Chauhan, A., Sharma, K. & Choudhary, S. Transition metal induced-magnetization in zigzag SiCNTs. J Comput Electron 22, 964–970 (2023). https://doi.org/10.1007/s10825-023-02030-y  (IMPACT FACTOR: 2.1)
Abstract : In this paper, we report the induced magnetization in metallic and semiconducting SiCNTs on the adsorption of transition metals. The resultant adsorbed SiCNTs structures showed half-metal-ferromagnetic and ferromagnetic behaviour verifying the induced magnetization. The spin-density of states and bandstructure have also been studied, confirming the induced magnetic behaviour. The strength of the induced ferromagnetic behaviour is varied with the various transition metals and is then related to the calculated magnetic moment in the adsorbed structure. The Cr adsorbed (8,0) SiCNT indicated strong half- metal-ferromagnetic behaviour with a magnetic moment of 5.4 μB. Only Cu-adsorbed (6,0) metallic SiCNT showed ferromagnetic behaviour among all the simulated structures indicating the impact of transition metal on the SiCNT structures. These promising results will be helpful in designing of devices like spin-valves, MTJs, and MRAMs in the field of spintronics.

Chauhan, A., Tomar, P. First-Principles Study of Enhanced Absorption in Van der Waals Heterostructure of MoS2/Cd0.90Zn0.10Te0.93Se0.07 in the Visible Region. J. Electron. Mater.(2022). https://doi.org/10.1007/s11664-022-09901-3 (IMPACT FACTOR: 2.1)
Abstract : To explore the optoelectronic characteristics of the quaternary compound, cadmium zinc telluride selenium (Cd0.90Zn0.10Te0.93Se0.07), and monolayer MoS2, DFT simulations are performed on the van der Waals (vdW) heterostructure. Cd0.90Zn0.10Te0.93Se0.07 and monolayer MoS2 are investigated and found to exhibit absorption in the ranges of ∼180 to 350 nm and ∼150 to 300 nm, respectively, and the MoS2/Cd0.90Zn0.10Te0.93Se0.07heterostructure showed in a redshift phenomenon with low absorption outside the visible region. The absorption coefficient (αα) shifted towards a higher wavelength with selective absorption in the range ∼450 to 640 nm with negligible interference from the UV and infrared regions. This consistent absorption in the visible spectrum demonstrates its uses in optoelectronics and suggests its possibility as a suitable material for solar cells. These findings have been corroborated by the results obtained for the refractive index (η) and dielectric constant (ε).
URL : doi.org/10.1007/s11664-022-09901-3 

Chauhan, A., Maahich, A. & Pal, J. First-principles calculations of the electronic and optical properties of WSe2/Cd0.9Zn0.1Te van der Waals heterostructure. J Comput Electron (2021). https://doi.org/10.1007/s10825-021-01659-x. (IMPACT FACTOR: 2.1)
Abstract: Electronic and optical properties of monolayer tungsten selenide $$(\text {WSe}_2)$$and cadmium zinc telluride $$(\text {Cd}_{0.9}\text {Zn}_{0.1}\text {Te})$$heterostructure with VdW, i.e., Van der Waals attractions between two layers, are explored using first-principles calculations. From the results, it is discovered that the proposed heterostructure of $$\text {WSe}_2/\text {Cd}_{0.9}\text {Zn}_{0.1}\text {Te}$$results into nearly direct band gap semiconducting material and has staggered (Type-II) band gap alignment which is required for opto electronic applications. Moreover, the results suggest that for monolayer $$\text {WSe}_2$$and $$\text {Cd}_{0.9}\text {Zn}_{0.1}\text {Te}$$, optical absorption is significant in a limited range of visible spectrum ($$\approx$$ 420–470 nm) and ($$\approx$$ 390–430 nm), respectively, but more absorption takes place in the infrared (IR) region for individual layers. However, the absorption in the $$\text {WSe}_2/\text {Cd}_{0.9}\text {Zn}_{0.1}\text {Te}$$heterostructure results in the red shift phenomenon and high absorption is achieved in the entire visible spectrum ($$\approx$$ 410–710 nm). Along with the absorption spectrum, dielectric function, refractive index and optical conductivity of the heterostructure are also calculated agreeing with the trends of each other. Desirable band alignment and high absorption coefficient in the visible spectrum can find applications in photovoltaic cells and other opto electronic devices.
URL: https://doi.org/10.1007/s10825-021-01659-x

Choudhary, S., Chauhan, A. First-principles study of spin transport in CrO2-SiCNT-CrO2 magnetic tunnel junction. J Comput Electron 14, 852–856 (2015). https://doi.org/10.1007/s10825-015-0725-x. (IMPACT FACTOR: 2.1)
Abstract: We report the spin transport in silicon carbide nanotube based magnetic tunnel junction with half-metallic-ferromagnet $$\hbox {CrO}_{2}$$as electrodes. The simulations based on first principles suggest high tunnel magnetoresistance $$\sim $$100 % at zero bias, TMR remains high at higher bias voltages. I–V characteristics show that spin current in parallel magnetic configuration is much higher than the spin current in anti-parallel configuration. Perfect spin-filtration effect is obtained for this structure. Transmission coefficients are also calculated to understand the spin and bias dependent non-equilibrium transport properties.
URL: https://doi.org/10.1007/s10825-015-0725-x

A. Chauhan and R. Dubey, "CNTFET-based Design of Ternary Adders based on GDI Technique," 2023 3rd International Conference on Innovative Mechanisms for Industry Applications (ICIMIA), Bengaluru, India, 2023, pp. 1369-1373, doi: 10.1109/ICIMIA60377.2023.10426029.
Abstract: The design of ternary adders based on the GDI approach employing Carbon Nanotube Field Effect Transistors (CNTFET) is presented in this study. Binary logic gates have always been the foundation of digital computing systems, but with increasing demand for high computational efficiency and low power consumption, the ternary logic is used. Ternary logic provides fewer interconnections, compact circuitry, and faster computations in advanced computing systems. The proposed design provides less power consumption, better speed, and less chip area than existing designs. The fundamental criterion for a VLSI system nowadays is low power consumption, which can be addressed by lowering the number of transistors on the device. As a result, the gates are designed using the Gate Diffusion Input (GDI) technique. Instead of using MOS, CNTFET is used as they have less power consumption and provide higher speed. Integrating all these advantages results in highly efficient computational logic like a half adder and a full adder. For the design purpose the Stanford CNTEFT model- Verilog A with 32nm technology and the tool for the simulation purpose Cadence Virtuoso is used.
URL:ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10426029&isnumber=10425793  

A. Chauhan, A. K. Meena and A. Kumar, "Performance Analysis of 4-Bit Multiplier using 90nm Technology," 2022 2nd International Conference on Intelligent Technologies (CONIT), 2022, pp. 1-5, doi: 10.1109/CONIT55038.2022.9848209.
Abstract: This paper explores three different 4-bit multipliers built using a modified full adder at the 90nm technology and compares low-power, high-speed multiplier designs with their CMOS counterparts. Since the multiplier block consumes a lot of power and plays a big part in the circuit's speed, the proposed multiplier will help in optimizing and enhancing the circuit performance. Our analysis results suggest that the proposed multipliers offer a decrease in power up to ~47.6%, a decrease in delay up to ~63.96%, and a decrease in transistor count up to ~58.7% when compared with the CMOS based designs.
URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9848209&isnumber=9847665

L. Mahor, A. Chauhan and P. Tiwari, "Parity Preserving Reversible Design Using FinFETs," 2019 1st International Conference on Signal Processing, VLSI and Communication Engineering (ICSPVCE), 2019, pp. 1-6, doi: 10.1109/ICSPVCE46182.2019.9092779.
Abstract: In this article we have developed parity preserving logic with the help of FinFET using reversible logic. Parity preserving reversibility allows the design to be fault tolerant as well as power efficient. Performance of the proposed design is validated by implementing full adder and ALU using FinFET with Cadence Virtuoso at 10nm. The design is approximately 50% better than the previously proposed designs along with preserving parity and reversibility.
URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9092779&isnumber=9092775

A. Chauhan, L. Mahor and P. Tiwari, "Low Power Quaternary Adder Using CNFET," 2020 IEEE VLSI DEVICE CIRCUIT AND SYSTEM (VLSI DCS), 2020, pp. 109-114, doi: 10.1109/VLSIDCS47293.2020.9179898.
Abstract: Binary logic and MOS devices have been in use since the inception of the design era, but now due to advancement in VLSI industry binary logic has become tedious and complicated. To overcome this challenge Multi-valued logic (MVL) such as ternary and Quaternary Logic (QTL) can be used. MVL designs have an advantage over binary logic designs with respect to the chip area and the complexity of interconnection. In this paper, we present the design and performance analysis of QTL Full Adder (QFA) using Carbon Nano-tube Field Effect Transistor (CNFET). For design purposes, we have used the Stanford Virtual-Source Carbon Nanotube Field Effect Transistor Model version 1.01 with sub 10nm CNFET technology. The design tool used for simulation is Cadence Virtuoso. The proposed QFA design has been compared against the existing CNFET based QTL designs and it is found that the proposed QFA design is 97-98% better in terms of Power Delay Product (PDP) and Energy Delay Product.
URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9179898&isnumber=9179848

A. Chauhan, K. K. Saini, N. Rajput and R. Domah, "Implementation of High Performance 4-Bit ALU using Dual Mode Pass Transistor Logic," 2021 International Conference on Intelligent Technologies (CONIT), 2021, pp. 1-4, doi: 10.1109/CONIT51480.2021.9498553.
Abstract: In this paper, we present a four bit arithmetic logic unit which is energy efficient and temperature invariant implemented using the dual mode pass transistor logic. The basic logic gates such as NOR and NAND are designed using both CMOS logic and dual mode pass transistor logic and are used in the proposed design. Simulations performed demonstrated that DMPL can reduce the computed worst case delay by 42.39%and 39.13%for NOR and NAND gates respectively in dynamic mode and average power dissipation by 67.96%and 24.09%for NOR and NAND gates respectively in static mode. In the implemented Arithmetic and Logic Unit, we observe a reduction in worst case delay and average power dissipation by 62.67%and 28.28%. The proposed logic was implemented in 90nm bulk technology using Cadence® Virtuoso® Schematic Editor.
URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9498553&isnumber=9498265

A. Chauhan, A. Kumari, P. Meena and S. K. Meena, "Performance Analysis of Optical Communication System for Various Filtering Operations Using MIMO FSO System under Fog Condition," 2021 International Conference on Intelligent Technologies (CONIT), 2021, pp. 1-5, doi: 10.1109/CONIT51480.2021.9498509.
Abstract: In this paper FSO MIMO technology has been used to analyze distinct pre and pre-post amplified optical filters under fog condition. Optical filters provide larger bandwidth with MIMO technology for several applications in 5G communication. Gaussian, Bessel and Rectangle optical filters have been used in this analysis for 5G optical communication. Optical filters are compared in terms of different parameters i.e. beam divergence, range, diameter of transmitter and receiver aperture under fog condition. The results have been plotted for various optical filters based on different parameters. The Q-factor is 765.80 at the range of 100 m for Gaussian optical filter.
URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9498509&isnumber=9498265

A. Chauhan, R. Verma, A. Joshi and R. Sharma, "Design and Performance Analysis for Underground Trains using Optisystem," 2021 International Conference on Intelligent Technologies (CONIT), 2021, pp. 1-4, doi: 10.1109/CONIT51480.2021.9498461.
Abstract: In this study, Wireless Optical Communication LOS model for underground trains to station based on FSO is designed and simulated to achieve optimum performance and reduced bit error ratio. The FSO medium is highly dependent on Air Quality and Weather conditions bit error ratio vary depending on the conditions. The aim of this design is to achieve a lower Bit error ratio and to increase the range for the communication. The simulation is designed to improve the quality of communication through FSO channel by reducing the bit error ratio through filtering techniques. The results of this simulation will help future research and implementations of the FSO based wireless optical communication for underground trains. This simulation is based on V2I architecture where the communication is based on FSO technology.
URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9498461&isnumber=9498265