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Title: Effect of graphene on photoluminescence properties of graphene/GeSi quantum dot hybrid structures

Graphene has been discovered to have two effects on the photoluminescence (PL) properties of graphene/GeSi quantum dot (QD) hybrid structures, which were formed by covering monolayer graphene sheet on the multilayer ordered GeSi QDs sample surfaces. At the excitation of 488 nm laser line, the hybrid structure had a reduced PL intensity, while at the excitation of 325 nm, it had an enhanced PL intensity. The attenuation in PL intensity can be attributed to the transferring of electrons from the conducting band of GeSi QDs to the graphene sheet. The electron transfer mechanism was confirmed by the time resolved PL measurements. For the PL enhancement, a mechanism called surface-plasmon-polariton (SPP) enhanced absorption mechanism is proposed, in which the excitation of SPP in the graphene is suggested. Due to the resonant excitation of SPP by incident light, the absorption of incident light is much enhanced at the surface region, thus leading to more exciton generation and a PL enhancement in the region. The results may be helpful to provide us a way to improve optical properties of low dimensional surface structures.
Authors:
; ; ; ; ; ; ; ;  [1] ; ;  [2]
  1. State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education) and Department of Physics, Fudan University, Shanghai 200433 (China)
  2. SHU-SolarE R and D Lab, Department of Physics, College of Science, Shanghai University, Shanghai 200444 (China)
Publication Date:
OSTI Identifier:
22311061
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 2; 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; ABSORPTION; ATTENUATION; COVERINGS; ELECTRON TRANSFER; ELECTRONS; EXCITATION; GERMANIUM SILICIDES; GRAPHENE; HYBRID SYSTEMS; LASER RADIATION; LAYERS; OPTICAL PROPERTIES; PHOTOLUMINESCENCE; QUANTUM DOTS; SURFACES; TIME RESOLUTION; VISIBLE RADIATION