Low-bias negative differential resistance in graphene nanoribbon superlattices

Abstract

We theoretically investigate negative differential resistance (NDR) for ballistic transport in semiconducting armchair graphene nanoribbon (aGNR) superlattices (5 to 20 barriers) at low bias voltages VSD < 500 mV. We combine the graphene Dirac hamiltonian with the Landauer-Büttiker formalism to calculate the current ISD through the system. We find three distinct transport regimes in which NDR occurs: (i) a "classical" regime for wide layers, through which the transport across bandgaps is strongly suppressed, leading to alternating regions of nearly unity and zero transmission probabilities as a function of VSD due to crossing of bandgaps from different layers. (ii) a quantum regime dominated by superlattice miniband conduction, with current suppression arising from the misalignment of miniband states with increasing VSD; and (iii) a Wannier-Stark ladder regime with current peaks occurring at the crossings of Wannier-Stark rungs from distinct ladders. We observe NDR at voltage biases as low as 10 mV with a high current density, making the aGNR superlattices attractive for device applications.

Pseudosaturation and Negative Differential Conductance in Graphene Field-Effect Transistors

“…Devices exhibiting a negative differential conductance (NDC) are also of strong interest for high-frequency applications. With different physical origins, this effect has been predicted in different kinds of graphene nanoribbon or nanomesh junctions [17]- [23], in graphene superlattices [24], in resonant tunneling diodes [25], [26], in FETs [27], and in tunnel FETs [28]. It has been even observed experimentally in a graphene FET as a consequence of ambipolar transport behavior [29].…”

Negative Differential Resistance and Steep Switching in Chevron Graphene Nanoribbon Field-Effect Transistors

“…Nonetheless, significant difficulty in synthesizing atomically precise, eptiaxial heterostructures has made it very challenging to realize such superlattice structures [2][3][4][5][6][7][8] . Much work has been done on modeling graphene nanoribbon heterostructures and superlattices which could exhibit NDR [9][10][11][12][13][14][15] . Other work has been done on steep slope devices based on GNR and CNT heterojunctions 16,17 .…”

Electronic Bloch oscillation in bilayer graphene gradient superlattices

“…This raises the questions of the existence and interesting properties of BO in graphene-based superlattices (GSLs). However, only a few works showing properties of BO related with graphene until now [17][18][19][20][21][22], and its experimental realization is still in vacancy.In this letter, we investigate EBO in bilayer graphene gradient superlattices, and propose a general way to control the BO. BLG is an attractive candidate for transistor applications since it has a tunable gap which varies in proportion to the electric field perpendicular to the…”

“…Later until 1992, the appearance of semiconductor superlattices, which have a long periodicity d and a narrow miniband width, makes the observation of EBO and WSLs possible [7][8][9]. Since then, BO has been investigated extensively in semicoductor superlattices both theoretically and experimentally [2,9].Recently, the experimental realization of graphene superlattices [10,11] has drawn much attentions [12][13][14][15][16][17][18][19][20][21][22]. In graphene, the low-energy charge carries behave as massless Dirac fermions, which leads to many interesting electronic properties, and the bilayer graphene (BLG) provides a semiconductor with a gap tunable by the electric field effect [23,24].…”

“…Recently, the experimental realization of graphene superlattices [10,11] has drawn much attentions [12][13][14][15][16][17][18][19][20][21][22]. In graphene, the low-energy charge carries behave as massless Dirac fermions, which leads to many interesting electronic properties, and the bilayer graphene (BLG) provides a semiconductor with a gap tunable by the electric field effect [23,24].…”