PMID- 33410418
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20251115
IS  - 1361-6528 (Electronic)
IS  - 0957-4484 (Linking)
VI  - 32
IP  - 13
DP  - 2021 Jan 6
TI  - Understanding ambipolar transport in MoS(2)field effect transistors: the 
      substrate is the key.
LID - 10.1088/1361-6528/abd27a [doi]
AB  - 2D materials offer a pathway for further scaling of CMOS technology. However, for 
      this to become a reality, both n-MOS and p-MOS should be realized, ideally with 
      the same (standard) material. In the specific case of MoS(2)field effect 
      transistors (FETs), ambipolar transport is seldom reported, primarily due to the 
      phenomenon of Fermi level pinning (FLP). In this study we identify the possible 
      sources of FLP in MoS(2)FETs and resolve them individually. A novel contact 
      transfer technique is used to transfer contacts on top of MoS(2)flake devices 
      that results in a significant increase in the hole branch of the transfer 
      characteristics as compared to conventionally fabricated contacts. We hypothesize 
      that the pinning not only comes from the contact-MoS(2)interface, but also from 
      the MoS(2)-substrate interface. We confirm this by shifting to an hBN substrate 
      which leads to a 10 fold increase in the hole current compared to the 
      SiO(2)substrate. Furthermore, we analyse MoS(2)FETs of different channel 
      thickness on three different substrates, SiO(2), hBN and Al(2)O(3), by 
      correlating the p-branchI(ON)/I(OFF)to the position of oxide defect band in these 
      substrates. FLP from the oxide is reduced in the case of Al(2)O(3)which enables 
      us to observe ambipolar transport in a bilayer MoS(2)FET. These results highlight 
      that MoS(2)is indeed an ambipolar material, and the absence of ambipolar 
      transport in MoS(2)FETs is strongly correlated to its dielectric environment and 
      processing conditions.
CI  - (c) 2021 IOP Publishing Ltd. All rights, including for text and data mining, AI 
      training, and similar technologies, are reserved.
FAU - Mootheri, Vivek
AU  - Mootheri V
AUID- ORCID: 0000-0002-1373-8405
AD  - Department of Materials Engineering (MTM), KU Leuven, Belgium.
AD  - IMEC, Kapeldreef 75, Leuven, Belgium.
FAU - Leonhardt, Alessandra
AU  - Leonhardt A
AUID- ORCID: 0000-0002-1110-6949
AD  - Department of Chemistry, KU Leuven, B-3001 Leuven, Belgium.
AD  - IMEC, Kapeldreef 75, Leuven, Belgium.
FAU - Verreck, Devin
AU  - Verreck D
AD  - IMEC, Kapeldreef 75, Leuven, Belgium.
FAU - Asselberghs, Inge
AU  - Asselberghs I
AD  - IMEC, Kapeldreef 75, Leuven, Belgium.
FAU - Huyghebaert, Cedric
AU  - Huyghebaert C
AUID- ORCID: 0000-0001-6043-7130
AD  - IMEC, Kapeldreef 75, Leuven, Belgium.
FAU - de Gendt, Stefan
AU  - de Gendt S
AD  - Department of Chemistry, KU Leuven, B-3001 Leuven, Belgium.
AD  - IMEC, Kapeldreef 75, Leuven, Belgium.
FAU - Radu, Iuliana
AU  - Radu I
AD  - IMEC, Kapeldreef 75, Leuven, Belgium.
FAU - Lin, Dennis
AU  - Lin D
AD  - IMEC, Kapeldreef 75, Leuven, Belgium.
FAU - Heyns, Marc
AU  - Heyns M
AD  - Department of Materials Engineering (MTM), KU Leuven, Belgium.
AD  - IMEC, Kapeldreef 75, Leuven, Belgium.
LA  - eng
PT  - Journal Article
DEP - 20210106
PL  - England
TA  - Nanotechnology
JT  - Nanotechnology
JID - 101241272
SB  - IM
OTO - NOTNLM
OT  - 2D materials
OT  - Al2O3
OT  - MoS2
OT  - ambipolar transport
OT  - graphene
OT  - hBN
OT  - transferred contacts
EDAT- 2021/01/08 06:00
MHDA- 2021/01/08 06:01
CRDT- 2021/01/07 08:39
PHST- 2020/10/16 00:00 [received]
PHST- 2020/12/09 00:00 [accepted]
PHST- 2021/01/08 06:01 [medline]
PHST- 2021/01/08 06:00 [pubmed]
PHST- 2021/01/07 08:39 [entrez]
AID - 10.1088/1361-6528/abd27a [doi]
PST - epublish
SO  - Nanotechnology. 2021 Jan 6;32(13). doi: 10.1088/1361-6528/abd27a.