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Pramanik A, Thakur S, Singh B, Willke P, Wenderoth M, Hofsäss H, Di Santo G, Petaccia L, Maiti K. Anomalies at the Dirac Point in Graphene and Its Hole-Doped Compositions. PHYSICAL REVIEW LETTERS 2022; 128:166401. [PMID: 35522498 DOI: 10.1103/physrevlett.128.166401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 03/28/2022] [Indexed: 06/14/2023]
Abstract
We study the properties of the Dirac states in SiC-graphene and its hole-doped compositions employing angle-resolved photoemission spectroscopy and density functional theory. The symmetry-selective measurements for the Dirac bands reveal their linearly dispersive behavior across the Dirac point which was termed as the anomalous region in earlier studies. No gap is observed even after boron substitution that reduced the carrier concentration significantly from 3.7×10^{13} cm^{-2} in SiC-graphene to 0.8×10^{13} cm^{-2} (5% doping). The anomalies at the Dirac point are attributed to the spectral width arising from the lifetime and momentum broadening in the experiments. The substitution of boron at the graphitic sites leads to a band renormalization and a shift of the Dirac point towards the Fermi level. The internal symmetries appear to be preserved in SiC-graphene even after significant boron substitutions. These results suggest that SiC-graphene is a good platform to realize exotic science as well as advanced technology where the carrier properties like concentration, mobility, etc., can be tuned keeping the Dirac fermionic properties protected.
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Affiliation(s)
- Arindam Pramanik
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Sangeeta Thakur
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
- Elettra Sincrotrone Trieste, Strada Statale 14 km 163.5, 34149 Trieste, Italy
| | - Bahadur Singh
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Philip Willke
- IV. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - Martin Wenderoth
- IV. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - Hans Hofsäss
- II. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - Giovanni Di Santo
- Elettra Sincrotrone Trieste, Strada Statale 14 km 163.5, 34149 Trieste, Italy
| | - Luca Petaccia
- Elettra Sincrotrone Trieste, Strada Statale 14 km 163.5, 34149 Trieste, Italy
| | - Kalobaran Maiti
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
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Rigosi AF, Liu CI, Glavin NR, Yang Y, Hill HM, Hu J, Hight Walker AR, Richter CA, Elmquist RE, Newell DB. Electrical Stabilization of Surface Resistivity in Epitaxial Graphene Systems by Amorphous Boron Nitride Encapsulation. ACS OMEGA 2017; 2:2326-2332. [PMID: 28828410 PMCID: PMC5562289 DOI: 10.1021/acsomega.7b00341] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 05/17/2017] [Indexed: 05/30/2023]
Abstract
Homogeneous monolayer epitaxial graphene (EG) is an ideal candidate for the development of millimeter-sized devices with single-crystal domains. A clean fabrication process was used to produce EG-based devices, with n-type doping level of the order of 1012 cm-2. Generally, electrical properties of EG, such as longitudinal resistivity, remain unstable when devices are exposed to air due to adsorption of molecular dopants, whose presence shifts the carrier density close to the Dirac point (<1010 cm-2) or into the p-type regime. Here, we report experimental results on the use of amorphous boron nitride (a-BN) as an encapsulation layer, whereby EG can maintain its longitudinal resistivity and have its carrier density modulated. Furthermore, we exposed 12 devices to controlled temperatures of up to 85 °C and relative humidity of up to 85% and reported that an approximately 20 nm a-BN encapsulation thickness is sufficient to preserve their longitudinal resistivity to within 10% of the previously measured value. We monitored the electronic properties of our encapsulated and nonencapsulated EG samples by magnetotransport measurements, using a neodymium iron boron magnet. Our results have essential importance in the mass production of millimeter-scale graphene devices, with stable electrical properties.
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Affiliation(s)
- Albert F. Rigosi
- Physical
Measurement Laboratory (PML), National Institute
of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - Chieh-I Liu
- Physical
Measurement Laboratory (PML), National Institute
of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
- Graduate
Institute of Applied Physics, National Taiwan
University, No. 1, Sec.
4, Roosevelt Road, Taipei 10617, Taiwan
| | - Nicholas R. Glavin
- Materials
and Manufacturing Directorate, Air Force
Research Laboratory, 2941 Hobson Way, Wright-Patterson AFB, Dayton Ohio 45433, United States
| | - Yanfei Yang
- Physical
Measurement Laboratory (PML), National Institute
of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
- Joint
Quantum Institute, University of Maryland, Bldg 224, Stadium Drive, College Park, Maryland 20742, United States
| | - Heather M. Hill
- Physical
Measurement Laboratory (PML), National Institute
of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - Jiuning Hu
- Physical
Measurement Laboratory (PML), National Institute
of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - Angela R. Hight Walker
- Physical
Measurement Laboratory (PML), National Institute
of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - Curt A. Richter
- Physical
Measurement Laboratory (PML), National Institute
of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - Randolph E. Elmquist
- Physical
Measurement Laboratory (PML), National Institute
of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - David B. Newell
- Physical
Measurement Laboratory (PML), National Institute
of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
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