April 9, 2021

GRAPHENE SEMINAR: Graphene Zener-Klein tunneling transistors

BERNARD PLAÇAIS

Research Director at CNRS

 

ABSTRACT:

High-mobility boron-nitride encapsulated graphene is a well-known model system for quantum electronics, spintronics, plasmonics, optolectronics, and strongly interacting electron physics. It is also a platform for out-of-equilibrium physics thanks to its electric-field strength and large current carrying capability. I will illustrate some high-field graphene properties in the geometry of the so-called Zener-Klein-tunneling transistor.

I will first introduce the Zener-Klein tunneling field effect transistor (ZKT-FET) istelf [1], its different transport regimes in increasing electric field: diffusive, velocity saturation, Zener-Klein tunneling, and finally the drain-voltage induced bipolar regime where the graphene transistor behaves as a light emitting diode (ZKT-LED).

Different regimes have signatures in the energy relaxation mechanisms which are monitored by microwave noise thermometry. In particular, ZKT-FETs benefit from electroluminescent cooling by the hyperbolic phonon polariton (HPhP) modes of the hBN substrate [2]. This near-field radiative cooling is quite unique and efficient; it can be directly detected as a mid-infrared light in the far-field. Conversely, HPhP emission plays an important role in the mid-infrared response ZKT-FETs [3].

If time permits, I will discuss two more phenomena observed in ZKT-FETs. The first is the breakdown of quantum Hall effect (QHE), which is mediated by a collective magneto-exciton instability [4]. The second revisits the old problem of flicker noise at the light of the tunability of relation mechanisms in ZKT-FETs.

[1] W. Yang et al., Nat. Nanotech. 13, 47 (2018)
[2] E. Baudin et al., Adv. Funct. Mater., 1904783 (2019)
[3] P. Huang et al., Nature Comm. 11, 863 (2020)
[4] W. Yang et al., Phys. Rev. Lett. 121, 136804 (2018)

 

Friday April 9, 2021, 12:00. Online

Hosted by Prof Dr Adrian Bachtold

 

ZOOM LINK TO JOIN IN

This seminar is open to all interested. Please, register to get the Zoom link to join in.

 

 

This activity is co-funded by the European Regional Development Funds (ERDF) allocated to the Programa operatiu FEDER de Catalunya 2014-2020, with the support of the Secretaria d’Universitats i Recerca of the Departament d’Empresa i Coneixement of the Generalitat de Catalunya for emerging technology clusters devoted to the valorization and transfer of research results (GraphCAT 001-P-001702).