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Title: Negative infrared photocurrent response in layered WS{sub 2}/reduced graphene oxide hybrids

We report high performance IR photocurrent response of two-dimensional hybrid materials consisting of layered WS{sub 2} nanosheets and reduced graphene oxide (RGO). Comparative photocurrent response studies of WS{sub 2} nanosheets, RGO, and WS{sub 2}/RGO hybrids were carried out by performing current-voltage (I-V) and time-dependent current measurements with a laser excitation source having a wavelength of 808 nm. The experimental investigations indicate that WS{sub 2}/RGO hybrids show negative photocurrent response, whereas WS{sub 2} and RGO show positive photocurrent response. The negative photocurrent response of the WS{sub 2}/RGO hybrids is explained using a band alignment diagram and attributed to a charge transfer mechanism between WS{sub 2} and RGO. This analysis is further corroborated by first-principles density functional calculations. The fabricated device based on WS{sub 2}/RGO hybrids shows a photosensitivity R{sub λ} of about 6 AW{sup −1} and a quantum efficiency η of ∼924%, which demonstrates high sensitivity of the hybrid material towards IR detection. WS{sub 2}/RGO hybrids are therefore promising candidates for potential applications in optoelectronic circuits and low cost, high performance, and reliable photodetectors.
Authors:
;  [1] ;  [2] ;  [3] ;  [1] ;  [4]
  1. School of Basic Sciences, Indian Institute of Technology, Bhubaneswar 751013 (India)
  2. Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)
  3. CSIR-National Chemical Laboratory, Physical and Materials Chemistry Division, Dr. Homi Bhabha Road, Pune 411008 (India)
  4. (United States)
Publication Date:
OSTI Identifier:
22395558
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 24; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CARBON OXIDES; DENSITY FUNCTIONAL METHOD; ELECTRIC POTENTIAL; EXCITATION; GRAPHENE; INFRARED RADIATION; LASER RADIATION; NANOSTRUCTURES; PHOTODETECTORS; PHOTOSENSITIVITY; POTENTIALS; QUANTUM EFFICIENCY; SHEETS; TIME DEPENDENCE; TUNGSTEN SULFIDES; TWO-DIMENSIONAL SYSTEMS