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Title: Improvement of graphene field-effect transistors by hexamethyldisilazane surface treatment

We report the improvement of the electrical characteristics of graphene field-effect transistors (FETs) by hexamethyldisilazane (HMDS) treatment. Both electron and hole field-effect mobilities are increased by 1.5 × –2×, accompanied by effective residual carrier concentration reduction. Dirac point also moves closer to zero Volt. Time evolution of mobility data shows that mobility improvement saturates after a few hours of HMDS treatment. Temperature-dependent transport measurements show small mobility variation between 77 K and room temperature (295 K) before HMDS application. But mobility at 77 K is almost 2 times higher than mobility at 295 K after HMDS application, indicating reduced carrier scattering. Performance improvement is also observed for FETs made on hydrophobic substrate–an HMDS-graphene-HMDS sandwich structure. Raman spectroscopic analysis shows that G peak width is increased, G peak position is down shifted, and intensity ratio between 2D and G peaks is increased after HMDS application. We attribute the improvements in electronic transport mainly to enhanced screening and mitigation of adsorbed impurities from graphene surface upon HMDS treatment.
Authors:
; ; ; ; ;  [1]
  1. Microelectronics Research Center, The University of Texas at Austin, Austin, Texas 78758 (United States)
Publication Date:
OSTI Identifier:
22311160
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 3; 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; CARRIER MOBILITY; CARRIERS; FIELD EFFECT TRANSISTORS; GRAPHENE; IMPURITIES; MITIGATION; REDUCTION; SCATTERING; SUBSTRATES; SURFACE TREATMENTS; SURFACES; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0065-0273 K; TEMPERATURE RANGE 0273-0400 K