Angle-Dependent Carrier Transmission in Graphene p–n Junctions

Abstract

Angle-dependent carrier transmission probability in graphene p-n junctions is investigated. Using electrostatic doping from buried gates, p-n junctions are formed along graphene channels that are patterned to form different angles with the junction. A peak in the junction resistance is observed, which becomes pronounced with angle. This angular dependence is observed for junctions made on both exfoliated and CVD-grown graphene and is consistent with the theoretically predicted dependence of transmission probability on incidence angle.

Unconventional Carrier Transport and Switching with Graphene PN Junction

“…Therefore the conductance modulation would not occur for non-chiral, non-relativistic electrons with isotropic transmission. The results follow closely with recent transport measurements of a tilted GPNJ in a structure that has separately controlled split-gate voltages [46,2]. We present an exact analytical solution to the spinor mismatch problem as well as NEGF based atomistic calculation for device sizes quite close to the experimental dimensions.…”

“…This is analogous to what is known as a Veselago lens in optics with negative refractive index metamaterials [36] and comes with its own Snell's law. Such eletron trajectory is accompanied with graphene's equivalent Fresnel's equations, which dictate the transmission probability depending upon the incident angle of the carrier [37,2]. Compared to uniformly doped graphene, we have higher control over the conductance in GPNJ with gate voltage [38].…”

“…The choice of substrate has proved to be crucial in graphene electron transport properties. Graphene on SiO 2 substrate has been studied extensively and in most cases the mobility is limited to 2000-4000 cm 2 /V-s [33,2] due to the presence of impurity scattering and phonons. Dean et.…”

“…2.14) enhancement due to a tilt in the junction. This time we vary the doping along the diagonal (orange line in (b)) as done in the experiment [2].…”

Angle-dependent bandgap engineering in gated graphene superlattices

“…In fact, recently, important steps have been made in order to find out the angular contribution of Dirac electrons to the transport properties in graphene-based devices. [58][59][60][61] Specifically, some groups have been able to discriminate the angular contribution by using tilting metallic electrodes (top gates) in single-barrier graphene structures. Likewise, it is also relevant to advance in the fabrication of cleaner samples and narrower gates in order to obtain potential profiles closer to abrupt, or to explore other possibilities to create potential barriers, and at the end superlattices, like electron-irradiated fluorinated graphene.…”