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Sobin Mathew

Address: Kozhikode, Kerala, India

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Papers by Sobin Mathew

Research paper thumbnail of Evaluation of Hysteresis Response in Achiral Edges of Graphene Nanoribbons on Semi-Insulating SiC

Materials Science Forum

Hysteresis response of epitaxially grown graphene nanoribbons devices on semi-insulating 4H-SiC i... more Hysteresis response of epitaxially grown graphene nanoribbons devices on semi-insulating 4H-SiC in the armchair and zigzag directions is evaluated and studied. The influence of the orientation of fabrication and dimensions of graphene nanoribbons on the hysteresis effect reveals the metallic and semiconducting nature graphene nanoribbons. The hysteresis response of armchair based graphene nanoribbon side gate and top gated devices implies the influence of gate field electric strength and the contribution of surface traps, adsorbents, and initial defects on graphene as the primary sources of hysteresis. Additionally, passivation with AlOx and top gate modulation decreased the hysteresis and improved the current-voltage characteristics.

Research paper thumbnail of Three-Dimensional MoS2 Nanosheet Structures: CVD Synthesis, Characterization, and Electrical Properties

Crystals, Mar 4, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Designing MoS2 channel properties for analog memory in neuromorphic applications

Journal of Vacuum Science & Technology B

In this paper, we introduce analog nonvolatile random access memory cells for neuromorphic comput... more In this paper, we introduce analog nonvolatile random access memory cells for neuromorphic computing. The analog memory cell [Formula: see text] channel is designed based on the simulation model including Fowler–Nordheim tunneling through a charge-trapping stack, trapping process, and transfer characteristics to describe a full write/read circle. 2D channel materials provide scaling to higher densities as well as preeminent modulation of the conductance by the accumulated space charge from the oxide trapping layer. In this paper, the main parameters affecting the distribution of memory states and their total number are considered. The dependence of memory state distribution on channel doping concentration and the number of layers is given. In addition, how the nonlinearity of memory state distribution can be overcome by variation of operating conditions and by applying pulse width modulation to the bottom gate voltage is also shown.

Research paper thumbnail of Hysteresis Associated with Intrinsic-Oxide Traps in Gate-Tunable Tetrahedral CVD-MoS2 Memristor

2022 IEEE 22nd International Conference on Nanotechnology (NANO)

Research paper thumbnail of Nanoscale surface morphology modulation of graphene – i-SiC heterostructures

A multitude gratings design consists of gratings with different pitches ranging from the micromet... more A multitude gratings design consists of gratings with different pitches ranging from the micrometre down to sub 40 nm scale combined with sub 10 nm step heights modulating the surface morphology for length scale measurements is proposed. The surface morphology modulation was performed using electron beam lithography incorporating a standard semiconductor processing technology. The critical dimension, edge roughness, step heights and line morphology in dependence on the grating pitch is studied.

Research paper thumbnail of Evaluation of Hysteresis Response in Achiral Edges of Graphene Nanoribbons on Semi-Insulating SiC

Materials Science Forum

Hysteresis response of epitaxially grown graphene nanoribbons devices on semi-insulating 4H-SiC i... more Hysteresis response of epitaxially grown graphene nanoribbons devices on semi-insulating 4H-SiC in the armchair and zigzag directions is evaluated and studied. The influence of the orientation of fabrication and dimensions of graphene nanoribbons on the hysteresis effect reveals the metallic and semiconducting nature graphene nanoribbons. The hysteresis response of armchair based graphene nanoribbon side gate and top gated devices implies the influence of gate field electric strength and the contribution of surface traps, adsorbents, and initial defects on graphene as the primary sources of hysteresis. Additionally, passivation with AlOx and top gate modulation decreased the hysteresis and improved the current-voltage characteristics.

Research paper thumbnail of Three-Dimensional MoS2 Nanosheet Structures: CVD Synthesis, Characterization, and Electrical Properties

Crystals, Mar 4, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Designing MoS2 channel properties for analog memory in neuromorphic applications

Journal of Vacuum Science & Technology B

In this paper, we introduce analog nonvolatile random access memory cells for neuromorphic comput... more In this paper, we introduce analog nonvolatile random access memory cells for neuromorphic computing. The analog memory cell [Formula: see text] channel is designed based on the simulation model including Fowler–Nordheim tunneling through a charge-trapping stack, trapping process, and transfer characteristics to describe a full write/read circle. 2D channel materials provide scaling to higher densities as well as preeminent modulation of the conductance by the accumulated space charge from the oxide trapping layer. In this paper, the main parameters affecting the distribution of memory states and their total number are considered. The dependence of memory state distribution on channel doping concentration and the number of layers is given. In addition, how the nonlinearity of memory state distribution can be overcome by variation of operating conditions and by applying pulse width modulation to the bottom gate voltage is also shown.

Research paper thumbnail of Hysteresis Associated with Intrinsic-Oxide Traps in Gate-Tunable Tetrahedral CVD-MoS2 Memristor

2022 IEEE 22nd International Conference on Nanotechnology (NANO)

Research paper thumbnail of Nanoscale surface morphology modulation of graphene – i-SiC heterostructures

A multitude gratings design consists of gratings with different pitches ranging from the micromet... more A multitude gratings design consists of gratings with different pitches ranging from the micrometre down to sub 40 nm scale combined with sub 10 nm step heights modulating the surface morphology for length scale measurements is proposed. The surface morphology modulation was performed using electron beam lithography incorporating a standard semiconductor processing technology. The critical dimension, edge roughness, step heights and line morphology in dependence on the grating pitch is studied.

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