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The effect of three different interlayer stacking arrangements of bilayer (BL) molybdenum disulfide (MoS2) channel material on the device behavior of p- and n-metal–oxide–semiconductor field-effect transistors (MOSFETs) is extensively investigated using first-principles calculation based on density functional theory, emphasizing electronic properties such as the eigenstates, effective mass, band structure, and total energy of the BL-MoS2 for various stacking arrangements. The corresponding effects on the MOSFET device characteristics are then analyzed. The results indicate that the hole effective masses in both the longitudinal (transport) and transverse direction are highly sensitive to the interlayer stacking arrangement, and the performance of the p-MOSFET can be significantly tuned for a suitable stacking configuration of the BL-MoS2. Indeed, 24.12% and 31.37% improvements in the on-state current and transconductance are observed, respectively, for the p-MOSFET compared with the natural stacking arrangement of BL-MoS2. The ballistic BL-MoS2-based p- and n-MOSFETs with the tuned stacking arrangement demonstrate an on-state current on the order of 103 µA/µm along with an on-state/off-state current ratio greater than 103, a near-ideal (> 65 mV/decade) subthreshold swing, and small (

In this work, the bi-layer (2L) Molybdenum Di-Sulfide i.e. MoS 2 at different stacking orientation are investigated under applied biaxial strain using first principle calculations. The 2L-MoS 2 has been considered in their natural stacking orientation for 2H-phase as well as in three other artificial stacking orientations achieved through appropriate in-plane rotations and translations of one atomic layer with respect to the other. Furthermore, each stacking orientations of MoS 2 are subjected to biaxial compressive and tensile strains and subsequent modulation of electronic properties in each of these cases are extensively analyzed. In this context, emphasize has been given on the effective masses and energy band-gaps of 2L-MoS 2 structures. The influence of strain on the energy band structures has been analyzed in details from the orbital projections of electronic states near the conduction band minima and valence band maxima.

In the proposed paper, dual band cavity backed substrate integrated waveguide (SIW) antenna is designed and analyzed. The dual frequency operation is achieved using L-shaped slots. The designed antenna resonates at satellite communication frequency band of 8.9 GHz and 11.1 GHz with gain of 7.1 dBi and 2.2 dBi at resonance respectively.

In this work, for the first time, the tri-layer sandwiched Van der Waals heterostructures of SnS2 and MoSe2 are investigated using first principle calculations. In such heterostructures, a monolayer of SnS2 (MoSe2) is sandwiched between two MoSe2 (SnS2) layers. Subsequently, such heterostructures are considered in two different stacking orders, i.e. ABA and AAA corresponding to the natural stacking of bulk MoSe2 and SnS2, respectively. The structural and electronic properties of such tri-layer heterostructures are extensively analyzed in comparison with the homogeneous SnS2 and MoSe2 tri-layers. In this context, emphasis has been given on the bond length and bond angles of metal and chalcogen atoms at the sandwiched layers of heterostructures. Finally, the influences of the homogenous and heterogeneous sandwiched layers on the energy band structures have been analyzed in detail from the orbital projections of electronic states at the conduction band and valence band.

A temperature-dependent delay optimization model for a multilayered graphene nanoribbon (MLGNR) with top contact (TC-GNR), side contact (SC-GNR), and Cu-based nano-interconnects using a wire sizing method was applied to determine the delay for different interconnects widths (11 nm, 16 nm, and 22 nm) and lengths (10 μm, 50 μm, and 100 μm), being the first such model for TC-GNR, SC-GNR, and Cu interconnects applied at three different chip operating temperatures (233 K, 300 K, and 378 K). The results reveal that the SC-GNR requires ~ 3–6× and ~ 2–3× fewer repeaters w.r.t. the TC-GNR or Cu interconnect, and that the SC-GNR and Cu interconnects can achieve ~ 4–5× and ~ 2–2.5× reduction in repeater dimension compared with the TC-GNR interconnect. Meanwhile, the SC-GNR interconnect can achieve 73× less propagation delay w.r.t. the TC-GNR interconnect for interconnect width of 22 nm, interconnect length of 10 μm, and two different chip operating temperatures of 233 K and 300 K. Similarly, the Cu interconnect can achieve 6× less propagation delay w.r.t. the TC-GNR interconnect at interconnect width of 22 nm and 16 nm, interconnect length of 10 μm, and 300 K.

The paper presents an ab initio study of the 2-D insulators and their effect on the performance of a magnetic tunnel junction memory (MTJ) device. MTJ devices has been considered as an alternate to the charge based data storage cells due to its spin-polarised operation and high scaling probability. The use of 2-D insulators like X-(OH)2 (X: Ca and Mg) and h-BN (hexagonal-Boron Nitride) in such device would be interesting. The authors have calculated the band structures, density of states and effective mass of electrons and holes for the mono-layer of these three non-conventional 2-D insulators using the first principle calculations in density functional theory framework using Quantumwise ATK tool. The ab initio calculation yielded band gap (Eg) of 4.633, 4.685 and 4.249 eV for h-BN, Ca(OH)2 and Mg(OH)2, respectively. The effective mass of electrons was calculated as 0.621, 0.604 and 0.478 for single layer h-BN, Ca(OH)2 and Mg(OH)2, respectively. While for holes it is 0.834, 0.446 and 0.407, respectively for h-BN, Ca(OH)2 and Mg(OH)2. The MTJ device properties as tunneling-magneto resistance, differential TMR, parallel and anti-parallel resistance, differential resistance and spin transfer torque components (in-plane and out-of-plane) with these materials as composite dielectric has been reported in this paper using MTJ Lab tool. The performance of MTJ memory device with h-BN based composite dielectric is found better.

We investigate the effects of uniaxial tensile and compressive strain on the material and transport properties of semiconducting Carbon Nanotube and the device properties of Blue-Phosphorene-CNT heterojunction devices. We see that the material and transport properties of the semiconducting CNT can be tuned through the application of uniaxial strain. The device properties of the heterojunction can also be modulated by strain. The variation in the current is significant in tensile strain zone.

In this work, we present a computational study on the possibility of strain engineering in monolayer Black Phosphorus (black P) and Blue Phosphorus (blue P) based MOSFETs. The material properties like band structure, carrier effective masses, carrier densities at band extrema are evaluated using Generalized Gradient Approximation (GGA) in Density Functional Theory (DFT).Thereafter self-consistent Non-Equilibrium Greens Function (NEGF) simulations are carried out to study the device performance metrics (such as output characteristics, ON currents, transconductance etc.) of such strained black P and blue P based MOSFETs. Our simulations show that carrier effective masses in blue P are more sensitive to strain applied in both zigzag and armchair directions. Blue P is more responsive in strain engineering for n-MOS and p-MOS. Except for black P based FETs with strain in armchair direction, overall the blue P (black P) n-MOSFET (p-MOSFET) show moderate to significant improvement in performance with tensile (compressive) strain in the transport directions., 16 pages

In this work by means of ab-initio calculations and Non equilibrium Green's function (NEGF) simulation we look to investigate the effect of strain in MoS 2 armchair nanoribbon (ANR)-metal junctions. We consider a (10, 0) MoS 2 ANR and various metals as Ti, Cr, Al and Ag for contact material. The effect of strain both in plain and out of plain direction is considered. We calculated the work function variations, band-gaps and carrier effective masses with Density Functional Theory (DFT) calculation and evaluated the Schottky barriers with the Schottky-Mott formula. The currents through these barriers were then evaluated with NEGF calculations. Our results show a wide possibility of output current enhancement with Schottky barrier height modulation with the proper choice of strain and contact material combinations.

In this work, we investigate the layer dependency of Mos2channel material based Double Gate Schottky barrier MOSFET. In order to evaluate the transport properties due to this effect accurately, we have calculated the electronic properties of multilayer Mos2using density functional theory and incorporated those parameters in our analytical model for double Gate Schottky barrier MOSFET. A full description of the electron transport due to tunneling through the Schottky barrier and thermionic emission of electrons is computed in our model. Our results demonstrate that monolayer Mos2shows good device characteristics for logic applications, with ON/OFF ratio $\sim 10^{7}$ . As far as the layer dependency is concerned, more than two times higher drain current is achievable for the device made of the monolayer based channel than that of the five-layer based channel of Mos2. In Mos2, drive current, transconductance significantly reduced with increasing number of layer. The results obtained with our model concur with experimental reports.

This paper presents a theoretical study of tunneling current density and the leakage current through multi-layer (stacked) trapping layer in the gate dielectric in MOS non-volatile memory devices. Two different 2D materials ($$\hbox {MoS}_{2}$$MoS2 and black phosphorous) with a combination of high-k dielectric ($$\hbox {HfO}_{2}$$HfO2) have been used for the study with differently ordered stacks i.e., as trapping layer and substrate. The material properties of 2D materials like density of states, effective mass and band structure has been evaluated using density functional theory simulations. Using the Maxwell---Garnett effective medium theory we have calculated the effective barrier height, effective bandgap, effective dielectric constant and effective mass of the gate dielectric stacks. By applying WKB approximation in the multi-layer trapping layer we have studied the effect of the direct and Fowler---Nordheim tunneling currents. The leakage current in all the different stack combinations used has also been evaluated. The results obtained have shown to match the required dynamics of a memory device.

In this work, we investigate the contact and channel material dependency of the transport properties of Siticene and Armchair CNT based heterostructure devices. The Density of States (DOS) of the heterojunction materials and transport properties like Device Density of States, transmission eigenstate, transmission pathway, transmission spectrum and I-V characteristics of two structures — CNT-Si-CNT and Si-CNT-Si are investigated. We see that CNT-Silicene-CNT heterojunction gives higher current and it is more conducive for FET device application. This device also shows better transport properties in terms of transmission Eigenstate, Transmission pathway and IV characteristics.

Magnetic tunnel junctions (MTJ) have emerged as a possible alternative to charge based data storage cells. With the development in 2-dimensional materials, non-conventional insulators like 2D hexagonal boron nitride (hBN), Ca(OH) 2 and Mg(OH) 2 have emerged as possible dielectrics in future nanoscale devices. Thus it could be interesting to investigate the application of these materials as insulators in MTJ devices. In this work, we have studied the effect of Ca(OH) 2 , hBN and Mg(OH)2 based composite oxides in a MTJ device. The barrier height of the composite oxide and effective mass of the same has been calculated using Maxwell-Garnett model. With the MTJ Lab tool available at nanohub, device characteristics were calculated. We have studied various MTJ parameters like parallel and anti-parallel resistance and differential resistance, tunnelling magneto resistance (TMR) and differential TMR (DTMR), and the variation of spin transfer torque (STT) components (In-Plane and Out-of-Plane STT) with voltage.

We investigate the effect of tensile and compressive strain in Phosphorene FET. Different percentage of tensile and compressive strain are applied on monolayer Phosphorene along the zigzag edge and the corresponding effects on bandgap, electron effective mass and ON current are analyzed. The optimum strain region is observed at 4% tensile strain for Phosphorene for the application in FET device. About 8.5 times improvement in ON current was observed for this strain percentage.

We investigate the effect of stacking order of bilayer black phosphorene on the device properties of p-MOSFET and n-MOSFET. Two layers of black phosphorus are stacked in three different orders and are used as channel material in both n-MOSFET and p-MOSFET devices. The effects of different stacking orders on electron and hole effective masses and output characteristics of MOSFETs, such as ON currents, ON/OFF ratio, and transconductance are analyzed. Our results show that about 1.37 times and 1.49 times increase in ON current is possible along armchair and zigzag directions, respectively, 55.11% variation in transconductance is possible along armchair direction, by changing stacking orders (AA, AB, and AC) and about 8 times increase in ON current is achievable by changing channel orientation (armchair or zigzag) in p-MOSFET. About 14.8 mV/V drain induced barrier lowering is observed for both p-MOSFET and n-MOSFET, which signifies good immunity to short channel effects.