Impact ionization and the paradox of defects in transition metal dichalcogenide FETs

Abstract For developing high-performance, reliable, and robust electronic devices, fundamental analysis of the hot carrier dynamics, high field transport, and electrical breakdown mechanisms in transition metal dichalcogenide field effect transistors is essential, which is largely unknown. In this p...

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Main Authors: Rupali Verma, Utpreksh Patbhaje, Asif A. Shah, Aadil Bashir Dar, Mayank Shrivastava
Format: Article
Language:English
Published: Nature Portfolio 2025-03-01
Series:npj 2D Materials and Applications
Online Access:https://doi.org/10.1038/s41699-024-00521-5
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author Rupali Verma
Utpreksh Patbhaje
Asif A. Shah
Aadil Bashir Dar
Mayank Shrivastava
author_facet Rupali Verma
Utpreksh Patbhaje
Asif A. Shah
Aadil Bashir Dar
Mayank Shrivastava
author_sort Rupali Verma
collection DOAJ
description Abstract For developing high-performance, reliable, and robust electronic devices, fundamental analysis of the hot carrier dynamics, high field transport, and electrical breakdown mechanisms in transition metal dichalcogenide field effect transistors is essential, which is largely unknown. In this paper, using a combination of electrical measurements, high-field spatial electroluminescence measurements, and theoretical models, it is presented that the impact ionization in MoS2 is mediated via defects, i.e., assisted via defect-induced trap states. Several unique observations, such as threshold voltage left-shift, increased subthreshold slope, anticlockwise hysteresis in the output characteristics, and bias-dependent redistribution of the electric field, are recorded when biased in the impact ionization regime, which we discover is due to the field-dependent dynamic occupancy of the defect states. Finally, we confirm a unified mechanism of high field breakdown as a competition between avalanche breakdown and minority carrier injection-induced breakdown from the variation of spatial electroluminescence with the gate voltage.
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spelling doaj-art-bd2d5251dfa6466d89c507a545d87e592025-08-20T03:40:44ZengNature Portfolionpj 2D Materials and Applications2397-71322025-03-01911910.1038/s41699-024-00521-5Impact ionization and the paradox of defects in transition metal dichalcogenide FETsRupali Verma0Utpreksh Patbhaje1Asif A. Shah2Aadil Bashir Dar3Mayank Shrivastava4Department of Electronic Systems Engineering, Indian Institute of ScienceDepartment of Electronic Systems Engineering, Indian Institute of ScienceDepartment of Electronic Systems Engineering, Indian Institute of ScienceDepartment of Electronic Systems Engineering, Indian Institute of ScienceDepartment of Electronic Systems Engineering, Indian Institute of ScienceAbstract For developing high-performance, reliable, and robust electronic devices, fundamental analysis of the hot carrier dynamics, high field transport, and electrical breakdown mechanisms in transition metal dichalcogenide field effect transistors is essential, which is largely unknown. In this paper, using a combination of electrical measurements, high-field spatial electroluminescence measurements, and theoretical models, it is presented that the impact ionization in MoS2 is mediated via defects, i.e., assisted via defect-induced trap states. Several unique observations, such as threshold voltage left-shift, increased subthreshold slope, anticlockwise hysteresis in the output characteristics, and bias-dependent redistribution of the electric field, are recorded when biased in the impact ionization regime, which we discover is due to the field-dependent dynamic occupancy of the defect states. Finally, we confirm a unified mechanism of high field breakdown as a competition between avalanche breakdown and minority carrier injection-induced breakdown from the variation of spatial electroluminescence with the gate voltage.https://doi.org/10.1038/s41699-024-00521-5
spellingShingle Rupali Verma
Utpreksh Patbhaje
Asif A. Shah
Aadil Bashir Dar
Mayank Shrivastava
Impact ionization and the paradox of defects in transition metal dichalcogenide FETs
npj 2D Materials and Applications
title Impact ionization and the paradox of defects in transition metal dichalcogenide FETs
title_full Impact ionization and the paradox of defects in transition metal dichalcogenide FETs
title_fullStr Impact ionization and the paradox of defects in transition metal dichalcogenide FETs
title_full_unstemmed Impact ionization and the paradox of defects in transition metal dichalcogenide FETs
title_short Impact ionization and the paradox of defects in transition metal dichalcogenide FETs
title_sort impact ionization and the paradox of defects in transition metal dichalcogenide fets
url https://doi.org/10.1038/s41699-024-00521-5
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