Inhomogeneous hysteresis in local STM tunnel conductance with gate-voltage in single-layer MoS$_2$ on SiO$_2$

Fuente: arXiv
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Autori principali: Jana, Santu Prasad, Gupta, Suraina, Gupta, Anjan Kumar
Natura: Preprint
Pubblicazione: 2024
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author Jana, Santu Prasad
Gupta, Suraina
Gupta, Anjan Kumar
author_facet Jana, Santu Prasad
Gupta, Suraina
Gupta, Anjan Kumar
contents Randomly distributed traps at the MoS$_2$/SiO$_2$ interface result in non-ideal transport behavior, including hysteresis in MoS$_2$/SiO$_2$ field effect transistors (FETs). Thus traps are mostly detrimental to the FET performance but they also offer some application potential. Our STM/S measurements on atomically resolved few-layer and single-layer MoS$_2$ on SiO$_2$ show n-doped behavior with the expected band gap close to 2.0 and 1.4 eV, respectively. The local tunnel conductance with gate-voltage $V_{\rm g}$ sweep exhibits a turn-on/off at a threshold $V_{\rm g}$ at which the tip's Fermi-energy nearly coincides with the local conduction band minimum. This threshold value is found to depend on $V_{\rm g}$ sweep direction amounting to local hysteresis. The hysteresis is, expectedly, found to depend on both the extent and rate of $V_{\rm g}$-sweep. Further, the spatial variation in the local $V_{\rm g}$ threshold and the details of tunnel conductance Vs $V_{\rm g}$ behavior indicate inhomogenieties in both the traps' density and their energy distribution. The latter even leads to the pinning of the local Fermi energy in some regions. Further, some rare locations exhibit a p-doping with both p and n-type $V_{\rm g}$-thresholds in local conductance and an unusual hysteresis.
format Preprint
id arxiv_https___arxiv_org_abs_2409_03304
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Inhomogeneous hysteresis in local STM tunnel conductance with gate-voltage in single-layer MoS$_2$ on SiO$_2$
Jana, Santu Prasad
Gupta, Suraina
Gupta, Anjan Kumar
Mesoscale and Nanoscale Physics
Materials Science
Randomly distributed traps at the MoS$_2$/SiO$_2$ interface result in non-ideal transport behavior, including hysteresis in MoS$_2$/SiO$_2$ field effect transistors (FETs). Thus traps are mostly detrimental to the FET performance but they also offer some application potential. Our STM/S measurements on atomically resolved few-layer and single-layer MoS$_2$ on SiO$_2$ show n-doped behavior with the expected band gap close to 2.0 and 1.4 eV, respectively. The local tunnel conductance with gate-voltage $V_{\rm g}$ sweep exhibits a turn-on/off at a threshold $V_{\rm g}$ at which the tip's Fermi-energy nearly coincides with the local conduction band minimum. This threshold value is found to depend on $V_{\rm g}$ sweep direction amounting to local hysteresis. The hysteresis is, expectedly, found to depend on both the extent and rate of $V_{\rm g}$-sweep. Further, the spatial variation in the local $V_{\rm g}$ threshold and the details of tunnel conductance Vs $V_{\rm g}$ behavior indicate inhomogenieties in both the traps' density and their energy distribution. The latter even leads to the pinning of the local Fermi energy in some regions. Further, some rare locations exhibit a p-doping with both p and n-type $V_{\rm g}$-thresholds in local conductance and an unusual hysteresis.
title Inhomogeneous hysteresis in local STM tunnel conductance with gate-voltage in single-layer MoS$_2$ on SiO$_2$
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2409.03304