Papers by shoeib Babaee Touski
Significant Hydrogen Storage Performance Improvement in Lithiumless Pristine Ben4 and Mgn4 by In-Plane
Effects of S-vacancy on electrical performance of monolayer TMD nanoribbons field-effect transistor
Materials Science in Semiconductor Processing
arXiv (Cornell University), Aug 19, 2020
In this work, the electrical properties of monolayer InSb in the presence of biaxial strain using... more In this work, the electrical properties of monolayer InSb in the presence of biaxial strain using density functional theory are investigated. Here, we first explore the band structure of InSb with and without spin-orbit coupling (SOC) consideration. The electron and hole effective mass modify with SOC consideration. The electron and hole effective masses lowered two and ten times, respectively. The location of valleys in conduction and valence band for various strains are explored, and the corresponding effective masses are reported. A lower effective mass is obtained for both electron and hole with applying tensile strain, whereas, the bandgap closes for large tensile strain. A numeric fitting has applied to effective mass versus strain, and an equation for every curve is reported. Finally, the work function of this material for different strains is obtained.
Strain Engineering of Electronic and Spin Properties in Snx (X = P, as, Sb, Bi) Monolayers
SSRN Electronic Journal
Tuning electronic properties of MSb (M = C, Si, Ge and Sn) monolayers by strain engineering
Physica E: Low-dimensional Systems and Nanostructures, 2022
Journal of Physics: Condensed Matter, 2021
In this work, the structural, electrical, and optical properties of bilayer SiX (X= N, P, As, and... more In this work, the structural, electrical, and optical properties of bilayer SiX (X= N, P, As, and Sb) are studied using density functional theory. Five different stacking orders are considered for every compound and their structural properties are presented. The band structure of these materials demonstrates that they are indirect semiconductors. The out-of-plane strain has been applied to tune the bandgap and its electrical properties. The bandgap increases with tensile strain, whereas, compressive strain leads to semiconductor-to-metal transition. The sensitivity of the bandgap to the pressure is investigated and bilayer SiSb demonstrates the highest bandgap sensitivity to the pressure. These structures exhibit Mexican hat-like valence band dispersion that can be approved by a singularity in the density of states (DOS). The Mexican-hat coefficient can be tuned by out-of-plane strain. Optical absorption of these compounds shows that the second and lower valence bands due to the hig...
Deep transfer learning correlation study of electronic and spin properties in buckled III–V monolayers
Physica E: Low-dimensional Systems and Nanostructures, 2022
IEEE Transactions on Electron Devices, 2022
The electronic properties of a field-effect transistor with two different structures of MoSi2N4 a... more The electronic properties of a field-effect transistor with two different structures of MoSi2N4 and WSi2N4 monolayers as the channel material in the presence of biaxial strain are investigated. The band structures show that these compounds are semiconductors with an indirect bandgap. Their band gaps can be adjusted by applying in-plane biaxial strain. In the following, the variation of the energies of the valleys and corresponding effective masses with respect to the strain are explored. Finally, the strained MoSi2N4 or WSi2N4 are used as the channel of a p-type FET and the corresponding current-voltage characteristic is explored. The results show this FET has an ION/IOFF ratio larger than 10 6 and subthreshold swing in the range of 96-98 mV/dec. The ION/IOFF ratio of these compounds with respect to strain are compared.
Journal of Physics: Condensed Matter, 2020
In this paper, the electrical and spin properties of mono- and bilayer HfSSe in the presence of a... more In this paper, the electrical and spin properties of mono- and bilayer HfSSe in the presence of a vertical electric field are studied. The density functional theory is used to investigate their properties. Fifteen different stacking orders of bilayer HfSSe are considered. The mono- and bilayer demonstrate an indirect bandgap, whereas the bandgap of bilayer can be effectively controlled by the electric field. While the bandgap of bilayer closes at large electric fields and a semiconductor to metal transition occurs, the effect of a normal electric field on the bandgap of the monolayer HfSSe is quite weak. Spin–orbit coupling causes band splitting in the valence band and Rashba spin splitting in the conduction band of both mono- and bilayer structures. The band splitting in the valence band of the bilayer is smaller than a monolayer, however, the vertical electric field increases the band splitting in bilayer one. The stacking configurations without mirror symmetry exhibit Rashba spin...
arXiv: Mesoscale and Nanoscale Physics, 2020
In this work, the source structure of an n-type thin-film tunneling FET is engineered to get bett... more In this work, the source structure of an n-type thin-film tunneling FET is engineered to get better performance. An ultra-thin SiGe along with Si is used in the source of silicon-based TFET. Two structures are compared with conventional TFET, one, SiGe is located on the top of Si in the source and another one in reverse. Simulations approve these structures can reduce sub-threshold swing, OFF-current several times, and increase the ON-OFF ratio. Band diagram for conduction and valance bands are investigated and band to band tunneling (BTBT) generation rate is used to find better performance. We find current flows at Si in the source with the wider bandgap. Ge mole fraction of SiGe is varied and its effects on the performance of TFET are studied. The SiGe thickness for both structures is explored to obtain the best thickness for SiGe.
In this paper, spintronic properties of a mono-layer GaTe under biaxial and uniaxial strain is in... more In this paper, spintronic properties of a mono-layer GaTe under biaxial and uniaxial strain is investigated. Here, spin properties of two structures of GaTe, one with mirror symmetry and the other with inversion symmetry, is studied. We have also calculated the band structure of GaTe with and without spin-orbit coupling to find out the importance of spinorbit interaction (SOI) on its band structure. We find band gap can be modified by applying spin-orbit coupling in the presence of strain. We explore Mexican-hat dispersion for different structures and different strain. We find Mexican-hat can be tuned by strain however some cases shows any Mexican-hat. We calculate spinsplitting in conduction and valence band in the presence of strain where the structure with inversion symmetry doesn’t show any splitting. We find in some cases, GaTe indicates Rashba dispersion that can be adjusted by strain. The amount of Rashba parameters may be in the order of other reported two-dimensional materi...
Effects of spin-orbit coupling on the electronic properties of the buckled III–V monolayers
Journal of Magnetism and Magnetic Materials, 2021
Journal of Electronic Materials, 2020
A ferroelectric field-effect transistor (Fe-FET) with two-dimensional MoS 2 as the channel materi... more A ferroelectric field-effect transistor (Fe-FET) with two-dimensional MoS 2 as the channel material with and without contact resistance is explored and compared. A top-of-the-barrier model along with the ferroelectric model is used to investigate the device performance. The contact resistance can strongly affect the current-voltage characteristic. The Fe-FET with contact resistance requires a higher voltage to reach saturation. Increasing the ferroelectric thickness to a specified value decreases the output resistance, but further increase can compensate this, resulting in high output resistance. Increasing the ferroelectric thickness decreases the mean subthreshold swing in the upward and downward regime. This effect is greater for the downward regime, and the contact resistance can intensify it.
Negative differential resistance, rectification, tunable peak-current position and switching effects in an alanine-based molecular device
Journal of Medical Engineering & Technology, 2021
Abstract The transport properties of a molecular bio-electronic device based on the alanine amino... more Abstract The transport properties of a molecular bio-electronic device based on the alanine amino-acid are investigated. The considered device consists of an alanine molecule as the central potential-dot coupled to two zigzag graphene nanoribbon (ZGNR) conducting electrodes. The current–voltage characteristics of this dual tunnelling molecular junction are studied at two different optimised compositions of the central molecule. The proposed amino-acid based structure utilises the tunnelling coupling similar to that of semiconducting single-electron transistors (SETs) to avoid complications due to the atomic interfaces. The current–voltage characteristics show polarity-dependent behaviour making the device feasible of being applied as a molecular rectifier. Negative differential resistance (NDR) along with tuneable peak-current position has been also observed in the current–voltage characteristics. The device is also capable of being applied as a switch controllable by the central molecule orientation.
Structural and electronic properties of semi-buckled phase of III4–V4 monolayers
Physica E: Low-dimensional Systems and Nanostructures, 2021
Abstract A new phase of III4–V4 binary monolayers which is non-planar is presented. This new phas... more Abstract A new phase of III4–V4 binary monolayers which is non-planar is presented. This new phase which has a particular semi-buckling pattern, is more stable compared to the recently reported planar and III2–V2 ones. In this structure, group-III atoms are located in a hypothetical middling plane while group-V ones are buckling meanderingly around the mentioned plane. Except for B4Sb4 and B4Bi4, all considered binary compounds in this structure exhibit a direct bandgap at Γ -point. The obtained bandgaps are modified by the B3LYP functional leading to the higher values. Interestingly, the obtained bandgaps for a couple of compounds closely match the solar peak making them a fascinating candidate for the solar applications. The relative and dynamic stability analysis of the compounds are also presented. Since nanoflakes are extremely attractive for the application regarding catalysts and solar energy, here, the energy gap and photocatalytic characteristics for different compositions of ξ -structure III4–V4 nanoflakes are also investigated. Furthermore, their nanoflakes with different sizes are also studied due to their potential applications including two-dimensional photocatalyst . In this regard, the variation of the nanoflake energy gap with respect to its corresponding dimensions is also presented.
Journal of Physics D: Applied Physics, 2021
In this work, the electrical and spin properties of monolayer MoSi2X4 (X= N, P, As, and Sb) under... more In this work, the electrical and spin properties of monolayer MoSi2X4 (X= N, P, As, and Sb) under vertical strain are investigated. The band structures state that MoSi2N4 is an indirect semiconductor, whereas other compounds are direct semiconductors. The vertical strain has been selected to modify the electrical properties. The bandgap shows a maximum and decreases for both tensile and compressive strains. The valence band at K-point displays a large spin-splitting, whereas the conduction band has a negligible splitting. On the other hand, the second conduction band has a large spin-splitting and moves down under vertical strain which leads to a large spin-splitting in both conduction and valence bands edges. The projected density of states along with the projected band structure clarifies the origin of these large spin-splittings. These three spin-splittings can be controlled by vertical strain.
Physical Review B, 2021
In this paper, the structural, electrical, and spin properties of Janus Si 2 XY (X, Y = P, As, Sb... more In this paper, the structural, electrical, and spin properties of Janus Si 2 XY (X, Y = P, As, Sb, Bi) structures are studied using first-principles calculations. Elastic constants and phonon dispersion prove that all these structures are stable. The band structures of six compounds are studied and the electrical properties are compared. The charge density has been studied to discover the charge distribution in the conduction and valence bands. These compounds exhibit Rashba spin splitting at the and M valleys in the conduction band. Biaxial in-plane strain is used to control the electrical and spin properties. The conduction band minimum can be tuned between the , K, and M valleys by applying strain. The Rashba spin splitting around the and M valleys in the conduction bands of these structures can be improved by strain and have the potential for applications in spintronic devices.
Physical Review B, 2021
The electronic properties of antimonene, single-layer Sb, are attracting great attention. In this... more The electronic properties of antimonene, single-layer Sb, are attracting great attention. In this paper, spin transport in armchair antimonene nanoribbon (ASbNR) is investigated. Following the tight-binding model we calculate both the transmission probability and the conductance by means of the non-equilibrium Green's function (NEGF) method. The effects of an external electric field vertical to the ribbon plane are explored. Our results indicate that the spin-flip rate increases with the vertical electric field. Disorder effects on spin transport are addressed by considering the presence of charged impurities. It is found that charged impurities also enhance the spin-flip rate but to a lesser extent than the out-of-plane electric field.
Physica E: Low-dimensional Systems and Nanostructures, 2021
In this work, the electrical properties of bilayer Antimonene with different stacking orders are ... more In this work, the electrical properties of bilayer Antimonene with different stacking orders are studied. Density functional theory with van der Waals (vdW) correction is used to investigate the electrical performances. Two configurations demonstrate considerable bandgaps, whereas, the bandgaps are close to zero for other structures. The in-plane biaxial strain is applied to modify the electrical properties. The bandgap reaches a maximum at a specific strain level and then closes at more enormous compressive and tensile strains. The energy of three valleys (Γ, Q, and K) in the conduction band are explored with the strain. The conduction band minimum switches between these valleys with the strain. Two bands also contribute to the valence band maximum, and the energy of these two bands for various strains is investigated. Finally, the effective mass for the valleys of the conduction band and the valence band are obtained. The effective mass at Γ-valley demonstrates the lowest effective mass.
Journal of Magnetism and Magnetic Materials, 2020
In this paper, spin properties of monolayer MX (M=Ga, In and X=S, Se, Te) in the presence of stra... more In this paper, spin properties of monolayer MX (M=Ga, In and X=S, Se, Te) in the presence of strain are studied. Density functional theory is used to investigate spin properties. The strain changes modification of bandgap due to spin-orbit coupling, the results indicate the spin-orbit coupling has a higher effect in the compressive regime. Also, spin splitting in the conduction and valence bands respect to strain are compared for six materials. The location of conduction band minimum (CBM) imposed a type of spin properties. These materials with mirror symmetry can display the Rashba effect while M valley is located at CBM. Strain tunes the conduction band minimum in three valleys (K, M and Γ valleys) and determines which spin effect (spin splitting, Rashba splitting or no spin splitting) has occurred in each strain for every material. Lastly, the relation between the Rashba parameter and the atomic mass is explored and it is observed that there is a linear correlation between atomic mass and Rashba coefficient.
Uploads
Papers by shoeib Babaee Touski