Role of Metal Contacts in High-Performance Phototransistors Based on WSe 2 Monolayers

Handle URI:
http://hdl.handle.net/10754/338570
Title:
Role of Metal Contacts in High-Performance Phototransistors Based on WSe 2 Monolayers
Authors:
Zhang, Wenjing; Chiu, Ming-Hui; Chen, Chang-Hsiao; Chen, Wei; Li, Lain-Jong ( 0000-0002-4059-7783 ) ; Wee, Andrew Thye Shen
Abstract:
Phototransistors based on monolayer transition metal dichalcogenides (TMD) have high photosensitivity due to their direct band gap transition. However, there is a lack of understanding of the effect of metal contacts on the performance of atomically thin TMD phototransistors. Here, we fabricate phototransistors based on large-area chemical vapor deposition (CVD) tungsten diselenide (WSe2) monolayers contacted with the metals of different work function values. We found that the low Schottky-contact WSe2 phototransistors exhibit a very high photo gain (105) and specific detectivity (1014Jones), values higher than commercial Si- and InGaAs-based photodetectors; however, the response speed is longer than 5 s in ambient air. In contrast, the high Schottky-contact phototransistors display a fast response time shorter than 23 ms, but the photo gain and specific detectivity decrease by several orders of magnitude. Moreover, the fast response speed of the high Schottky-contact devices is maintained for a few months in ambient air. This study demonstrates that the contact plays an important role in TMD phototransistors, and barrier height tuning is critical for optimizing the photoresponse and photoresponsivity. © 2014 American Chemical Society.
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Citation:
Role of Metal Contacts in High-Performance Phototransistors Based on WSe 2 Monolayers 2014, 8 (8):8653 ACS Nano
Publisher:
American Chemical Society
Journal:
ACS Nano
Issue Date:
26-Aug-2014
DOI:
10.1021/nn503521c
Type:
Article
ISSN:
1936-0851; 1936-086X
Additional Links:
http://pubs.acs.org/doi/abs/10.1021/nn503521c
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorZhang, Wenjingen
dc.contributor.authorChiu, Ming-Huien
dc.contributor.authorChen, Chang-Hsiaoen
dc.contributor.authorChen, Weien
dc.contributor.authorLi, Lain-Jongen
dc.contributor.authorWee, Andrew Thye Shenen
dc.date.accessioned2015-01-20T06:08:11Z-
dc.date.available2015-01-20T06:08:11Z-
dc.date.issued2014-08-26en
dc.identifier.citationRole of Metal Contacts in High-Performance Phototransistors Based on WSe 2 Monolayers 2014, 8 (8):8653 ACS Nanoen
dc.identifier.issn1936-0851en
dc.identifier.issn1936-086Xen
dc.identifier.doi10.1021/nn503521cen
dc.identifier.urihttp://hdl.handle.net/10754/338570en
dc.description.abstractPhototransistors based on monolayer transition metal dichalcogenides (TMD) have high photosensitivity due to their direct band gap transition. However, there is a lack of understanding of the effect of metal contacts on the performance of atomically thin TMD phototransistors. Here, we fabricate phototransistors based on large-area chemical vapor deposition (CVD) tungsten diselenide (WSe2) monolayers contacted with the metals of different work function values. We found that the low Schottky-contact WSe2 phototransistors exhibit a very high photo gain (105) and specific detectivity (1014Jones), values higher than commercial Si- and InGaAs-based photodetectors; however, the response speed is longer than 5 s in ambient air. In contrast, the high Schottky-contact phototransistors display a fast response time shorter than 23 ms, but the photo gain and specific detectivity decrease by several orders of magnitude. Moreover, the fast response speed of the high Schottky-contact devices is maintained for a few months in ambient air. This study demonstrates that the contact plays an important role in TMD phototransistors, and barrier height tuning is critical for optimizing the photoresponse and photoresponsivity. © 2014 American Chemical Society.en
dc.language.isoenen
dc.publisherAmerican Chemical Societyen
dc.relation.urlhttp://pubs.acs.org/doi/abs/10.1021/nn503521cen
dc.rightsArchived with thanks to ACS Nanoen
dc.subjectPhotodetectoren
dc.subjectContact effecten
dc.subjectSchottky barrieren
dc.subjecttungsten diselenideen
dc.subject2D Materialen
dc.titleRole of Metal Contacts in High-Performance Phototransistors Based on WSe 2 Monolayersen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalACS Nanoen
dc.eprint.versionPost-printen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorLi, Lain-Jongen
kaust.authorChiu, Ming-Huien
All Items in KAUST are protected by copyright, with all rights reserved, unless otherwise indicated.