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Title: Spectroscopic ellipsometry on Si/SiO{sub 2}/graphene tri-layer system exposed to downstream hydrogen plasma: Effects of hydrogenation and chemical sputtering

In this work, the optical response of graphene to hydrogen plasma treatment is investigated with spectroscopic ellipsometry measurements. Although the electronic transport properties and Raman spectrum of graphene change after plasma hydrogenation, ellipsometric parameters of the Si/SiO2/graphene tri-layer system do not change. This is attributed to plasma hydrogenated graphene still being electrically conductive, since the light absorption of conducting 2D materials does not depend on the electronic band structure. A change in the light transmission can only be observed when higher energy hydrogen ions (30‚ÄČeV) are employed, which chemically sputter the graphene layer. An optical contrast is still apparent after sputtering due to the remaining traces of graphene and hydrocarbons on the surface. In brief, plasma treatment does not change the light transmission of graphene; and when it does, this is actually due to plasma damage rather than plasma hydrogenation.
Authors:
 [1] ;  [2] ; ; ; ; ;  [1]
  1. Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)
  2. (United States)
Publication Date:
OSTI Identifier:
22395642
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 1; Other Information: (c) 2015 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; ELECTRIC CONDUCTIVITY; ELLIPSOMETRY; EV RANGE; GRAPHENE; HYDROCARBONS; HYDROGEN; HYDROGEN IONS; HYDROGENATION; LAYERS; LIGHT TRANSMISSION; PLASMA; RAMAN SPECTRA; SILICA; SILICON OXIDES; SPUTTERING; SURFACES; VISIBLE RADIATION