skip to main content

SciTech ConnectSciTech Connect

Title: High-performance photocurrent generation from two-dimensional WS{sub 2} field-effect transistors

The generation of a photocurrent from two-dimensional tungsten disulfide (WS{sub 2}) field-effect transistors is examined here, and its dependence on the photon energy is characterized. We found from the WS{sub 2} devices that a significant enhancement in the ratio of illuminated current against dark current (I{sub illum}/I{sub dark}) of ∼10{sup 2}–10{sup 3} is attained, even with the application of electric fields of E{sub D} = 0.02 and E{sub G} = −22 mV/nm, which are much smaller than that of the bulk MoS{sub 2} phototransistor. Most importantly, we demonstrate that our multilayer WS{sub 2} shows an extremely high external quantum efficiency of ∼7000%, even with the smallest electrical field applied. We also found that photons with an energy near the direct band gap of the bulk WS{sub 2}, in the range of 1.9–2.34 eV, give rise to a photoresponsivity of ∼0.27 A/W, which exceeds the photoresponsivity of the bulk MoS{sub 2} phototransistor. The superior photosensing properties of WS{sub 2} demonstrated in this work are expected to be utilized in the development of future high performance two-dimensional optoelectronic devices.
Authors:
; ;  [1] ;  [2] ;  [3] ;  [1] ;  [4]
  1. Department of Nano Science and Technology, SKKU Advanced Institute of Nano-Technology (SAINT), Sungkyunkwan University (SKKU), 2066 Seobu-ro, Suwon-si, Gyeonggi-do 440-746 (Korea, Republic of)
  2. (SSGC), 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 440-746 (Korea, Republic of)
  3. Department of Materials Engineering, Korea Aerospace University, 76 Hanggongdaehang-ro, Deogyang-gu, Goyang-si, Gyeonggi-do 412-791 (Korea, Republic of)
  4. Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)
Publication Date:
OSTI Identifier:
22275530
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 19; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; FIELD EFFECT TRANSISTORS; MOLYBDENUM SULFIDES; PHOTONS; QUANTUM EFFICIENCY; TUNGSTEN SULFIDES