PMID- 19206449
OWN - NLM
STAT- MEDLINE
DCOM- 20090320
LR  - 20131121
IS  - 1936-086X (Electronic)
IS  - 1936-0851 (Linking)
VI  - 2
IP  - 10
DP  - 2008 Oct 28
TI  - n-Type behavior of graphene supported on Si/SiO(2) substrates.
PG  - 2037-44
LID - 10.1021/nn800354m [doi]
AB  - Results are presented from an experimental and theoretical study of the 
      electronic properties of back-gated graphene field effect transistors (FETs) on 
      Si/SiO(2) substrates. The excess charge on the graphene was observed by sweeping 
      the gate voltage to determine the charge neutrality point in the graphene. 
      Devices exposed to laboratory environment for several days were always found to 
      be initially p-type. After approximately 20 h at 200 degrees C in approximately 5 
      x 10(-7) Torr vacuum, the FET slowly evolved to n-type behavior with a final 
      excess electron density on the graphene of approximately 4 x 10(12) e/cm(2). This 
      value is in excellent agreement with our theoretical calculations on SiO(2), 
      where we have used molecular dynamics to build the SiO(2) structure and then 
      density functional theory to compute the electronic structure. The essential 
      theoretical result is that the SiO(2) has a significant surface state density 
      just below the conduction band edge that donates electrons to the graphene to 
      balance the chemical potential at the interface. An electrostatic model for the 
      FET is also presented that produces an expression for the gate bias dependence of 
      the carrier density.
FAU - Romero, Hugo E
AU  - Romero HE
AD  - Department of Physics, Pennsylvania State University, University Park, 
      Pennsylvania 16802, USA.
FAU - Shen, Ning
AU  - Shen N
FAU - Joshi, Prasoon
AU  - Joshi P
FAU - Gutierrez, Humberto R
AU  - Gutierrez HR
FAU - Tadigadapa, Srinivas A
AU  - Tadigadapa SA
FAU - Sofo, Jorge O
AU  - Sofo JO
FAU - Eklund, Peter C
AU  - Eklund PC
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PL  - United States
TA  - ACS Nano
JT  - ACS nano
JID - 101313589
RN  - 0 (Macromolecular Substances)
RN  - 7631-86-9 (Silicon Dioxide)
RN  - 7782-42-5 (Graphite)
RN  - Z4152N8IUI (Silicon)
SB  - IM
MH  - *Computer-Aided Design
MH  - Equipment Design
MH  - Equipment Failure Analysis
MH  - Graphite/*chemistry
MH  - Macromolecular Substances/chemistry
MH  - Materials Testing
MH  - Molecular Conformation
MH  - Nanostructures/*chemistry/ultrastructure
MH  - Nanotechnology/*instrumentation/methods
MH  - Particle Size
MH  - Silicon/*chemistry
MH  - Silicon Dioxide/*chemistry
MH  - Surface Properties
MH  - *Transistors, Electronic
EDAT- 2009/02/12 09:00
MHDA- 2009/03/21 09:00
CRDT- 2009/02/12 09:00
PHST- 2009/02/12 09:00 [entrez]
PHST- 2009/02/12 09:00 [pubmed]
PHST- 2009/03/21 09:00 [medline]
AID - 10.1021/nn800354m [pii]
AID - 10.1021/nn800354m [doi]
PST - ppublish
SO  - ACS Nano. 2008 Oct 28;2(10):2037-44. doi: 10.1021/nn800354m.