Nonvolatile Switching in Graphene Field-Effect Devices

Abstract

The absence of a band gap in graphene restricts its straight forward application as a channel material in field effect transistors. In this letter, we report on a new approach to engineer a band gap in graphene field effect devices (FED) by controlled structural modification of the graphene channel itself. The conductance in the FEDs is switched between a conductive "onstate" to an insulating "off-state" with more than six orders of magnitude difference in conductance. Above a critical value of an electric field applied to the FED gate under certain environmental conditions, a chemical modification takes place to form insulating graphene derivatives. The effect can be reversed by electrical fields of opposite polarity or short current pulses to recover the initial state. These reversible switches could potentially be applied to non-volatile memories and novel neuromorphic processing concepts.

Charge transfer equilibria in ambient-exposed epitaxial graphene on (0001¯) 6 H-SiC

“…[1][2][3][4][5] Although exfoliated graphene has been demonstrated as an ideal platform for proofof-concept research, [6][7][8] epitaxial graphene is the practical production route for electronics applications due to compatibility with wafer-scale processing techniques. 3,[9][10][11] The epitaxial system is characterized by an additional layer of complexity in the fact that the graphene now interacts not only with the ambient but also with the underlying substrate. A comprehensive analysis of the electronic and transport properties of this material in this complex environment is of paramount importance.…”

Nucleation and growth of thin films of rod-like conjugated molecules

“…Graphene [154,155] can be used as a transparent, flexible and highly conductive electrode for organic electronic applications [156,157]. The combination of optical active films of flat lying molecules on a transparent electrode materials is a promising route to high efficiency OLEDs.…”

High-performance solution of the transport problem in a graphene armchair structure with a generic potential

“…It is important to notice that although the envelope functions associated with different Dirac points decouple in the differential equations (8), they are in fact mixed by the boundary conditions (10). This coupling makes it nontrivial to define a symmetric discretization of (8).…”

“…A gap can be induced by the lateral confinement in narrow ribbons with a transverse size of a few nanometers or of tens of nanometers, which can be efficiently modeled with atomistic techniques, such as tight-binding approaches. Fabrication of such nanowires is, however, very challenging, and therefore also alternative and/or complementary approaches to open up a gap are being pursued, such as the usage of bilayer graphene [5][6][7][8], of chemical functionalization [9][10][11][12], and of doping [13][14][15][16]. Large graphene devices (with a size of several hundreds of nanometers or of microns) can, however, be convenient (or mandatory) in radio-frequency or sensor applications, which do not necessarily require an energy gap [17][18][19][20][21][22].…”