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Title: Spatially Resolved Photoexcited Charge-Carrier Dynamics in Phase-Engineered Monolayer MoS2

Journal Article · · ACS Nano
DOI:https://doi.org/10.1021/nn506469v· OSTI ID:1254836
 [1];  [1];  [2];  [3];  [3];  [4];  [1];  [3];  [3];  [2];  [1];  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Rutgers Univ., Piscataway, NJ (United States)
  3. Rice Univ., Houston, TX (United States)
  4. Pacific Light Technologies, Portland, OR (United States)

A fundamental understanding of the intrinsic optoelectronic properties of atomically thin transition metal dichalcogenides (TMDs) is crucial for its integration into high performance semiconductor devices. We investigate the transport properties of chemical vapor deposition (CVD) grown monolayer molybdenum disulfide (MoS2) under photo-excitation using correlated scanning photocurrent microscopy and photoluminescence imaging. We examined the effect of local phase transformation underneath the metal electrodes on the generation of photocurrent across the channel length with diffraction-limited spatial resolution. While maximum photocurrent generation occurs at the Schottky contacts of semiconducting (2H-phase) MoS2, after the metallic phase transformation (1T-phase), the photocurrent peak is observed towards the center of the device channel, suggesting a strong reduction of native Schottky barriers. Analysis using the bias and position dependence of the photocurrent indicates that the Schottky barrier heights are few meV for 1T- and ~200 meV for 2H-contacted devices. We also demonstrate that a reduction of native Schottky barriers in a 1T device enhances the photo responsivity by more than one order of magnitude, a crucial parameter in achieving high performance optoelectronic devices. The obtained results pave a pathway for the fundamental understanding of intrinsic optoelectronic properties of atomically thin TMDs where Ohmic contacts are necessary for achieving high efficiency devices with low power consumption.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
Grant/Contract Number:
AC52-06NA25396
OSTI ID:
1254836
Report Number(s):
LA-UR-14-29662
Journal Information:
ACS Nano, Vol. 9, Issue 1; ISSN 1936-0851
Publisher:
American Chemical SocietyCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 49 works
Citation information provided by
Web of Science

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Cited By (15)

Layer-dependent ultrafast dynamics of α -In 2 Se 3 nanoflakes journal May 2019
Atomic-layer soft plasma etching of MoS2 journal January 2016
Recent progress of TMD nanomaterials: phase transitions and applications journal January 2020
Ultrasensitive MoS2 photodetector by serial nano-bridge multi-heterojunction journal October 2019
Two-dimensional transition metal dichalcogenides: interface and defect engineering journal January 2018
Contact morphology and revisited photocurrent dynamics in monolayer MoS2 journal November 2017
A Versatile Scanning Photocurrent Mapping System to Characterize Optoelectronic Devices based on 2D Materials journal May 2017
Phase-selective synthesis of 1T′ MoS2 monolayers and heterophase bilayers journal October 2018
Photonic crystallization of two-dimensional MoS 2 for stretchable photodetectors journal January 2019
Diversity of structural and electronic properties of P –AuBr of different dimensions journal March 2019
Synthesis, stabilization and applications of 2-dimensional 1T metallic MoS 2 journal January 2018
Interactions between lasers and two-dimensional transition metal dichalcogenides journal January 2016
Schottky solar cell using few-layered transition metal dichalcogenides toward large-scale fabrication of semitransparent and flexible power generator journal September 2017
Contact morphology and revisited photocurrent dynamics in monolayer MoS2 preprint January 2017
Nanoscale imaging of the photoresponse in PN junctions of InGaAs infrared detector journal February 2016

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