Tunnel and electrostatic coupling in graphene-LaAlO<sub>3</sub>/SrTiO<sub>3</sub> hybrid systems

Aliaj, Ilirjan; Torre, Iacopo; Mišeikis, Vaidotas; Gennaro, Emiliano Di; Sambri, A.; Gamucci, A.; Coletti, Camilla; Beltram, Fabio; Granozio, F. Miletto; Polini, Marco; Pellegrini, Vittorio; Roddaro, Stefano

doi:10.1063/1.4953821

Cited by 11 publications

(10 citation statements)

References 46 publications

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“…Ideal for this purpose would be graphene with its monolayer thickness. Recently, transfer of small (tens of µm) graphene flakes on LAO/STO structures has been demonstrated (Aliaj et al 2016). A method of TOABr-assisted electrochemical delamination (Koefoed et al 2015) allows transfer of large (on the inch scale) graphene layers.…”

Section: Prospectsmentioning

confidence: 99%

Electrons and Polarons at Oxide Interfaces Explored by Soft-X-Ray ARPES

Strocov

Cancellieri

Mishchenko

2018

Springer Series in Materials Science

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Soft-X-ray ARPES (SX-ARPES) with its enhanced probing depth and chemical specificity allows access to fundamental electronic structure characteristics -momentum-resolved spectral function, band structure, Fermi surface -of systems difficult and even impossible for the conventional ARPES such as three-dimensional materials, buried interfaces and impurities. After a recap of the spectroscopic abilities of SX-ARPES, we review its applications to oxide interfaces, focusing on the paradigm LaAlO 3 /SrTiO 3 interface. Resonant SX-ARPES at the Ti L-edge accentuates photoemission response of the mobile interface electrons and exposes their d xy -, d yz -and d xz -derived subbands forming the Fermi surface in the interface quantum well. After a recap of the electron-phonon interaction physics, we demonstrate that peak-dip-hump structure of the experimental spectral function manifests the Holstein-type large polaron nature of the interface charge carriers, explaining their fundamentally reduced mobility. Coupling of the charge carriers to polar soft phonon modes defines dramatic drop of mobility with temperature. Oxygen deficiency adds another dimension to the rich physics of LaAlO 3 /SrTiO 3 resulting from co-existence of mobile and localized electrons introduced by oxygen vacancies. Oxygen deficiency allows tuning of the polaronic coupling and thus mobility of the charge carriers, as well as of interfacial ferromagnetism connected with various atomic configurations of the vacancies. Finally, we discuss spectroscopic evidence of phase separation at the LaAlO 3 /SrTiO 3 interface. Concluding, we put prospects of SX-ARPES for complex heterostructures, spin-resolving experiments opening the totally unexplored field of interfacial spin structure, and inoperando field-effect experiments paving the way towards device applications of the reach physics of oxide interfaces.

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Section: Prospectsmentioning

confidence: 99%

Electrons and Polarons at Oxide Interfaces Explored by Soft-X-Ray ARPES

Strocov

Cancellieri

Mishchenko

2018

Springer Series in Materials Science

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“…These two factors determine the asymmetric dark current densityvoltage characteristics. Using a simple model [22,31,32], as discussed in Supplementary Data 2, we calculate the flow of current in the device, obtaining the dash-dot red line in Fig. 3(a).…”

Section: Resultsmentioning

confidence: 99%

Graphene-Quantum Dots Hybrid Photodetectors with Low Dark-Current Readout

De Fazio,

Uzlu,

Torre

et al. 2020

Preprint

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Graphene-based photodetectors have shown responsivities up to 10 8 A/W and photoconductive gains up to 10 8 electrons per photon. These photodetectors rely on a highly absorbing layer in close proximity of graphene, which induces a shift of the graphene chemical potential upon absorption, hence modifying its channel resistance. However, due to the semi-metallic nature of graphene, the readout requires dark currents of hundreds of µA up to mA, leading to high power consumption needed for the device operation. Here we propose a novel approach for highly responsive graphenebased photodetectors with orders of magnitude lower dark current levels. A shift of the graphene chemical potential caused by light absorption in a layer of colloidal quantum dots, induces a variation of the current flowing across a metal-insulator-graphene diode structure. Owing to the low density of states of graphene near the neutrality point, the light-induced shift in chemical potential can be relatively large, dramatically changing the amount of current flowing across the insulating barrier, and giving rise to a novel type of gain mechanism. This readout requires dark currents of hundreds of nA up to few µA, orders of magnitude lower than other graphene-based photodetectors, while keeping responsivities of ∼70 A/W in the infrared, almost two orders of magnitude higher compared to established germanium on silicon and indium gallium arsenide infrared photodetectors. This makes the device appealing for applications where high responsivity and low power consumption are required.

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“…Ideal for this purpose would be graphene with its monolayer thickness. Recently, transfer of small (tens of μm) graphene flakes on LAO/STO structures has been demonstrated [217]. A method of TOABr-assisted electrochemical delamination [218] allows transfer of large (on the inch scale) graphene layers.…”

Section: Prospectsmentioning

confidence: 99%

Ab-Initio Calculations of TMO Band Structure

Filippetti

2018

Spectroscopy of Complex Oxide Interfaces

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The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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Tunnel and electrostatic coupling in graphene-LaAlO₃/SrTiO₃ hybrid systems

Cited by 11 publications

References 46 publications

Electrons and Polarons at Oxide Interfaces Explored by Soft-X-Ray ARPES

Electrons and Polarons at Oxide Interfaces Explored by Soft-X-Ray ARPES

Graphene-Quantum Dots Hybrid Photodetectors with Low Dark-Current Readout

Ab-Initio Calculations of TMO Band Structure

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Tunnel and electrostatic coupling in graphene-LaAlO3/SrTiO3 hybrid systems

Cited by 11 publications

References 46 publications

Electrons and Polarons at Oxide Interfaces Explored by Soft-X-Ray ARPES

Electrons and Polarons at Oxide Interfaces Explored by Soft-X-Ray ARPES

Graphene-Quantum Dots Hybrid Photodetectors with Low Dark-Current Readout

Ab-Initio Calculations of TMO Band Structure

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Product

Resources

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Tunnel and electrostatic coupling in graphene-LaAlO₃/SrTiO₃ hybrid systems