Influence of SiO<sub>2</sub> or h-BN substrate on the room-temperature electronic transport in chemically derived single layer graphene

Wang, Zhenping; Yao, Qiuyan; Hu, Yingbin; Li, Chuan; Hußmann, Marleen; Weintrub, Benjamin I.; Kirchhof, Jan N.; Bolotin, Kirill I.; Taniguchi, Takashi; Watanabe, Kenji; Eigler, Siegfried

doi:10.1039/c9ra09197a

Cited by 12 publications

(10 citation statements)

References 35 publications

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“…For G D transistors (Figure b–f), no Dirac point appears within the range of the scanned gate voltages from −50 V to +50 V. All samples show unipolar p‐type character. These defective G D samples are stronger p‐doped than the G 0 % sample due to the oxo‐groups modification of the graphene networks …”

Section: Figurementioning

confidence: 99%

Room‐Temperature Transport Properties of Graphene with Defects Derived from Oxo‐Graphene

Wang

Yao

Eigler

2020

Chemistry A European J

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In recent years, graphene oxide has been considered as as oluble precursor of graphene for electronic applications. However,t he performance lags behind that of graphene due to lattice defects. Here, the relation between the density of defects in the range of 0.2 %a nd 1.5 %a nd the transport properties is quantitatively studied. Therefore, the related flakes of monolayers of graphene were prepared from oxo-functionalized graphene (oxo-G). The morphologic structure of oxo-G was imaged by atomicf orce microscopy (AFM) and scanning tunneling microscopy (STM). Field-effect mobility values were determined to range between 0.3 cm 2 V À1 s À1 and 33.2 cm 2 V À1 s À1 ,w hich were inverselyp roportionalt ot he density of defects. These resultsp rovide the first quantitative description of the density of defects and transport properties, which plays an important role for potentiala pplications.Chemically modified graphene, such as graphene oxide (GO) or oxo-functionalized graphene (oxo-G), has received considerable interests for electronic, [1] optoelectronic, [2] biological [3] and chemicals ensing [4] applications due to its physicochemical phenomena, including its tunable bandgap, [5] diverse luminescence behaviors, [6] biological compatibility [7] and the ability to modify the surfacec ovalently and non-covalently. [8] In contrast to pristine graphene with carbona toms arranged into at wodimensional hexagonal lattice, oxo-G consists of abundant sp 3hybridized carbon atoms, which are covalently bound to oxogroups,m ainly hydroxyl and epoxy groups. [9] The sp 3 -portioni s between 4% and6 0%,w ith variable functionality. [10] The oxoaddends are tentatively immobilizedo nto segregatedc arbon, which isolates intact nanometer-scale graphene domains into small islands. [11] The existence of surface oxo-groups has profound impacts on improving its hydrophilicity, [12] chemicalreactivity, [13] catalytic activity, [14] and optical properties, [2a] whereas the effect is detrimental for the electrical conductivity. [15] Therefore, to enhancet he electrical performance of GO or oxo-G, extensiver esearches were conducted on the deoxygenation of oxo-addends. [16] In this regard, thermal processing provides a simple and versatile method for carbonization, however,w ithout ac arbon source, more lattice defects, such as few-atoms vacancies and nanometer-scale holes, are introduced due to thermald isproportionation along with CO 2 formation. [17] Duringt he oxidative synthesis of GO and oxo-G, defects are introducedi nto the carbon framework. [10a] They cannot be healedo ut by simple chemical reduction although oxo-addendsa re reductively defunctionalized from the carbon lattice by ac hemical reductant. [18] The defect concentrationi nG Oo r oxo-G can be determined by Ramans pectroscopy after chemical reduction and typically varies from 0.001 %t o2%. [19] We demonstrated that the mobility of chargec arriers of reduced oxo-G with ad ensity of defects as low as 0.02 %i se xceeding 1000 cm 2 V À1 s À1 ,m easureda t1 .6 Ki na...

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Section: Figurementioning

confidence: 99%

Room‐Temperature Transport Properties of Graphene with Defects Derived from Oxo‐Graphene

Wang

Yao

Eigler

2020

Chemistry A European J

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“…The large hysteresis between forward and reverse sweeps is induced by trapped charges. [23] The resistance and charge carrier mobility are extracted from the transport curves in Figure 1 C-J. As depicted in Figure 1 K, on-resistance of oxo-G FET at V ds = 0.5 V and V bg = 0 V decreases from 5.3 10 8 W to 3.3 10 5 W. Evolution of the resistances reveals that the oxo-G undergoes an insulator to conductor transition with a partial restoration of sp 2 -carbon lattices in the oxo-G flake by thermal processing.…”

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Identification of Semiconductive Patches in Thermally Processed Monolayer Oxo‐Functionalized Graphene

et al. 2020

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The thermal decomposition of graphene oxide (GO) is a complex process at the atomic level and not fully understood. Here, a subclass of GO, oxo-functionalized graphene (oxo-G), was used to study its thermal disproportionation. We present the impact of annealing on the electronic properties of a monolayer oxo-G flake and correlated the chemical composition and topography corrugation by twoprobe transport measurements, XPS, TEM, FTIR and STM. Surprisingly, we found that oxo-G, processed at 300 8C, displays CÀC sp 3-patches and possibly CÀOÀC bonds, next to graphene domains and holes. It is striking that those CÀOÀ C/C À C sp 3-separated sp 2-patches a few nanometers in diameter possess semiconducting properties with a band gap of about 0.4 eV. We propose that sp 3-patches confine conjugated sp 2-C atoms, which leads to the local semiconductor properties. Accordingly, graphene with sp 3-C in double layer areas is a potential class of semiconductors and a potential target for future chemical modifications.

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“…Alle Transporteigenschaften ( I ds – V bg ) zeigen ein typisches p‐Typ‐Verhalten (Abbildung C–J). Die große Hysterese zwischen Vorwärts‐ und Rückwärts‐Abtasten wird durch gebundene Ladungen induziert . Der Widerstand und die Ladungsträgermobilität werden aus den Transportkurven Abbildung C–J extrahiert.…”

Section: Methodsunclassified

“…Die große Hysterese zwischen Vorwärts-und Rückwärts-Abtasten wird durch gebundene Ladungen induziert. [36,37] Der Widerstand und die Ladungsträgermobilität werden aus den Transportkurven Abbildung 1 C-J extrahiert. Wie in Abbildung 1 K dargestellt, nimmt der Durchlasswiderstand des oxo-G-FET bei nimmt m h um eine Grçßenordnung zu.…”

Section: Zuschriftenunclassified

Identifizierung von halbleitenden Bereichen in thermisch behandeltem monolagigem Oxo‐funktionalisiertem Graphen

et al. 2020

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Die thermische Zersetzung von Graphenoxid (GO) ist auf atomarer Ebene ein komplexer Prozess und noch nicht vollständig verstanden. In dieser Untersuchung wurde eine Unterklasse von GO verwendet, oxofunktionalisiertes Graphen (oxo‐G), um die thermische Disproportionierung zu untersuchen. Wir stellen den Einfluss des Erhitzens auf die elektronischen Eigenschaften einer einschichtigen oxo‐G‐Flocke vor und korrelieren die chemische Zusammensetzung und die Topographie durch Zwei‐Kontakt‐Transportmessungen, XPS, TEM, FTIR und STM. Überraschenderweise fanden wir heraus, dass oxo‐G, das auf 300 °C erhitzt wurde, neben Graphendomänen und Löchern auch C‐C‐sp3‐Bereiche und möglicherweise C‐O‐C‐Bindungen enthält. Auffallend ist, dass diese C‐O‐C/C‐C‐sp3‐getrennten sp2‐Bereiche mit wenigen Nanometern Durchmesser Halbleitereigenschaften mit einer Bandlücke von etwa 0.4 eV aufweisen. Wir schlagen vor, dass sp3‐Bereiche konjugierte sp2‐C‐Atomgruppen einschließen, was zu den lokalen Halbleitereigenschaften führt. Dementsprechend ist Graphen mit sp3‐C in Doppelschichtbereichen eine potentielle Klasse von Halbleitern und ein potentielles Ziel für zukünftige chemische Modifikationen.

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Influence of SiO₂ or h-BN substrate on the room-temperature electronic transport in chemically derived single layer graphene

Abstract: Defects in graphene cause scattering and basal plane interactions shift the Dirac-point.

Cited by 12 publications

References 35 publications

Room‐Temperature Transport Properties of Graphene with Defects Derived from Oxo‐Graphene

Room‐Temperature Transport Properties of Graphene with Defects Derived from Oxo‐Graphene

Identification of Semiconductive Patches in Thermally Processed Monolayer Oxo‐Functionalized Graphene

Identifizierung von halbleitenden Bereichen in thermisch behandeltem monolagigem Oxo‐funktionalisiertem Graphen

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Influence of SiO2 or h-BN substrate on the room-temperature electronic transport in chemically derived single layer graphene

Abstract: Defects in graphene cause scattering and basal plane interactions shift the Dirac-point.

Cited by 12 publications

References 35 publications

Room‐Temperature Transport Properties of Graphene with Defects Derived from Oxo‐Graphene

Room‐Temperature Transport Properties of Graphene with Defects Derived from Oxo‐Graphene

Identification of Semiconductive Patches in Thermally Processed Monolayer Oxo‐Functionalized Graphene

Identifizierung von halbleitenden Bereichen in thermisch behandeltem monolagigem Oxo‐funktionalisiertem Graphen

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Influence of SiO₂ or h-BN substrate on the room-temperature electronic transport in chemically derived single layer graphene