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n-Type behavior of graphene supported on Si/SiO(2) substrates.
ACS Nano. 2008 Oct 28; 2(10):2037-44.AN

Abstract

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.

Authors+Show Affiliations

Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

19206449

Citation

Romero, Hugo E., et al. "N-Type Behavior of Graphene Supported On Si/SiO(2) Substrates." ACS Nano, vol. 2, no. 10, 2008, pp. 2037-44.
Romero HE, Shen N, Joshi P, et al. N-Type behavior of graphene supported on Si/SiO(2) substrates. ACS Nano. 2008;2(10):2037-44.
Romero, H. E., Shen, N., Joshi, P., Gutierrez, H. R., Tadigadapa, S. A., Sofo, J. O., & Eklund, P. C. (2008). N-Type behavior of graphene supported on Si/SiO(2) substrates. ACS Nano, 2(10), 2037-44. https://doi.org/10.1021/nn800354m
Romero HE, et al. N-Type Behavior of Graphene Supported On Si/SiO(2) Substrates. ACS Nano. 2008 Oct 28;2(10):2037-44. PubMed PMID: 19206449.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - n-Type behavior of graphene supported on Si/SiO(2) substrates. AU - Romero,Hugo E, AU - Shen,Ning, AU - Joshi,Prasoon, AU - Gutierrez,Humberto R, AU - Tadigadapa,Srinivas A, AU - Sofo,Jorge O, AU - Eklund,Peter C, PY - 2009/2/12/entrez PY - 2009/2/12/pubmed PY - 2009/3/21/medline SP - 2037 EP - 44 JF - ACS nano JO - ACS Nano VL - 2 IS - 10 N2 - 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. SN - 1936-086X UR - https://www.unboundmedicine.com/medline/citation/19206449/n_Type_behavior_of_graphene_supported_on_Si/SiO_2__substrates_ L2 - https://doi.org/10.1021/nn800354m DB - PRIME DP - Unbound Medicine ER -