Engineering high charge transfer n-doping of graphene electrodes and its application to organic electronics

Sanders, Simon; Cabrero-Vilatela, Andrea; Kidambi, Piran R.; Alexander-Webber, Jack A.; Weijtens, Christ H. L.; Braeuninger‐Weimer, Philipp; Aria, Adrianus Indrat; Qasim, Malik M.; Wilkinson, Timothy D.; Robertson, John; Hofmann, Stephan; Meyer, Jens

doi:10.1039/c5nr03246f

Cited by 43 publications

(41 citation statements)

References 49 publications

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“…For dye-sensitized solar cells [71][72][73], for instance, using ALD titania as the support layer would provide a clean interface between the graphene and the titania whilst the titania can also serve as a compact layer to reduce charge recombination losses [74]. It is conceivable that dopant materials could be incorporated at the graphene-oxide interface to strongly dope the graphene for applications requiring low sheet resistance such as organic light emitting diodes [75]. The oxide support may also be exploited as a hard mask [76] in devices avoiding the use of polymers and other organic solvents that can leave undesirable carbon residues on the graphene surface.…”

Section: Discussionmentioning

confidence: 99%

Atomic layer deposited oxide films as protective interface layers for integrated graphene transfer

et al. 2017

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The transfer of chemical vapour deposited graphene from its parent growth catalyst has become a bottleneck for many of its emerging applications. The sacrificial polymer layers that are typically deposited onto graphene for mechanical support during transfer are challenging to remove completely and hence leave graphene and subsequent device interfaces contaminated. Here, we report on the use of atomic layer deposited (ALD) oxide films as protective interface and support layers during graphene transfer. The method avoids any direct contact of the graphene with polymers and through the use of thicker ALD layers (≥100 nm), polymers can be eliminated from the transfer-process altogether. The ALD film can be kept as a functional device layer, facilitating integrated device manufacturing. We demonstrate back-gated field effect devices based on single-layer graphene transferred with a protective Al2O3 film onto SiO2 that show significantly reduced charge trap and residual carrier densities. We critically discuss the advantages and challenges of processing graphene/ALD bilayer structures.

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Section: Discussionmentioning

confidence: 99%

Atomic layer deposited oxide films as protective interface layers for integrated graphene transfer

et al. 2017

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“…Cs carbonate is widely used as an n-type dopant in organic light emitting diodes, and also can be used to dope graphene. 19 The carbonate precursor dissociates on heating to leave a Cs oxide, which may actually be a sub-oxide. We consider the oxide to be Cs 2 O.…”

Section: Graphene Supercell/dopant Supercellmentioning

confidence: 99%

“…15 On the other hand, for graphene as an electrode, it is useful to consider interstitial or charge transfer doping by physisorbed species. [17][18][19][20][21][22][23][24] These can dope the graphene n-or p-type, without necessarily creating defects. Transfer doping is also useful to increase the conductivity of contacts, as the high resistance of contacts to graphene in devices can limit the device performance.…”

Section: Introductionmentioning

confidence: 99%

Charge transfer doping of graphene without degrading carrier mobility

Guo

Robertson

2017

Journal of Applied Physics

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Density functional calculations are used to analyze the charge transfer doping mechanism by molecules absorbed onto graphene. Typical dopants studied are AuCl 3 , FeCl 3 , SbF 5 , HNO 3 , MoO 3 , Cs 2 O, O 2 , and OH. The Fermi level shifts are correlated with the electron affinity or ionization potential of the dopants. We pay particular attention to whether the dopants form direct chemisorptive bonds which cause the underlying carbon atoms to pucker to form sp 3 sites as these interrupt the p bonding of the basal plane, and cause carrier scattering and thus degrade the carrier mobility. Most species even those with high or low electronegativity do not cause puckering. In contrast, reactive radicals like-OH cause puckering of the basal plane, creating sp 3 sites which degrade mobility.

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“…In case of MoO 3 different doping mechanisms are reported. Some papers discuss charger-transfer induced due to annealing [32] and some discuss MoO 3 cluster formation due to multistage doping, without annealing [33][34][35][36][37]. Formation of metal carbide (Mo-C) with annealing at very high temperature is also reported [38].…”

Section: Introductionmentioning

confidence: 99%

Understanding noninvasive charge transfer doping of graphene: a comparative study

Mehta

Murugesan

et al. 2018

J Mater Sci: Mater Electron

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In this work, we systematically investigate and compare noninvasive doping of chemical vapor deposition graphene with three molecule dopants through spectroscopy and electrical conductivity techniques. Thionyl chloride shows the smallest improvement in conductivity with poor temporal and thermal stability and nitric acid induces the biggest sheet resistance reduction with modified stability. Molybdenum trioxide doping stands out, after thermal annealing, with both causing a significant sheet-resistance reduction and having superior temporal and thermal stability. These properties make it ideal for applications in advanced electronics. Theoretical studies based on the van der Waals density functional method suggest that cluster formation of molybdenum trioxide underpins the significant reduction in sheet resistance, and the stability, that arises after thermal annealing. Our comparative study clarifies charge transfer doping of graphene and brings understanding of the weak-interaction nature of such non-destructive doping of graphene. Our work also shows that we can use weak chemisorption to tailor the electronic properties of graphene, for example, to improve conductivity. This ability open up possibilities for further use of graphene in electronic interconnects, field effect transistors and other systems.

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Engineering high charge transfer n-doping of graphene electrodes and its application to organic electronics

Cited by 43 publications

References 49 publications

Atomic layer deposited oxide films as protective interface layers for integrated graphene transfer

Atomic layer deposited oxide films as protective interface layers for integrated graphene transfer

Charge transfer doping of graphene without degrading carrier mobility

Understanding noninvasive charge transfer doping of graphene: a comparative study

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