arXiv subjects

Tarun Kumar Agarwal

Publications and source records attributed to Tarun Kumar Agarwal.

3 recordsLinked to original sources

arXiv2025

Investigation of resistive switching in Au/MoS2/Au using Reactive Molecular Dynamics and ab-initio quantum transport calculations

In this work, we investigate the underlying physical mechanism for electric-field induced resistive switching in Au/MoS2/Au based memristive devices by combining reactive Molecular Dynamics (MD) and ab-initio quantum transport calculations. Using MD with Au/Mo/S ReaxFF potential, we observe the formation of realistic conductive filament consisting of gold atoms through monolayer MoS2 layer when sufficient electric field is applied. We furthermore instigate the rupture of the gold atom filament when a sufficiently large electric field is applied in the opposite direction. To calculate the conductance of the obtained structures and identify the High Resistance (HR) and Low Resistance (LR) states, we employ the ab-initio electron transport calculations by importing the atomic structures from MD calculations. For single-defect MoS2 memristors, the obtained LRS, HRS current densities are in order of 10^7 A/cm^2 which agrees reasonably well with the reported experiments.

cond-mat.mtrl-sci↗

arXiv2024

Investigating Metal Dopants for Lowering the Contact Resistance of Top Gold Contacted Monolayer MoS2

The interface properties between gold (Au) contacts and molybdenum disulfide (MoS2) are critical for optimizing the performance of semiconductor devices. This study investigates the impact of metal dopants (D) on the transport properties of MoS2 devices with top Au contacts, aiming to reduce contact resistance and enhance device performance. Using density functional theory (DFT) and non-equilibrium Green's function (NEGF)- based first-principles calculations, we examine the structural, electronic, and quantum transport properties of Au-contacted, metal-doped MoS2. Our results indicate that Cd, Re, and Ru dopants significantly improve the structural stability and electronic properties of MoS2. Specifically, formation energy calculations show that Cd and Re are stable at hollow sites, while Ru prefers bond sites. Remarkably, Au-Ru-MoS2-based device exhibits tunnel resistance (RT ) up to 4.82 ohm-um. Furthermore, a dual-gated Au-Ru-MoS2 field effect transistor (FET) demonstrates an impressive Ion/Ioff ratio of 10^8 at Vgs of 2 V, highlighting its potential for nano-switching applications.

cond-mat.mtrl-sci↗

arXiv2022

Modeling of High and Low Resistant States in Single Defect Atomristors

Resistance-change random access memory (RRAM) devices are nanoscale metal-insulator-metal structures that can store information in their resistance states, namely the high resistance (HRS) and low resistance (LRS) states. They are a potential candidate for a universal memory as these non-volatile memory elements can offer fast-switching, long retention and switching cycles, and additionally, are also suitable for direct applications in neuromorphic computing. In this study, we first present a model to analyze different resistance states of RRAM devices or so-called "atomristors" that utilize novel 2D materials as the switching materials instead of insulators. The developed model is then used to study the electrical characteristics of a single defect monolayer MoS$_{2}$ memristor. The change in the device resistance between the HRS and LRS is associated to the change in the tunneling probability when the vacancy defects in the 2D material are substituted by the metal atoms from the electrodes. The distortion due to defects and substituted metal atom is captured in the 1D potential energy profile by averaging the effect along the transverse direction. This simplification enables us to model single defect memristors with a less extensive quantum transport model while taking into account the presence of defects.

cs.ET↗