Pei - Shan Zhao

Learn More
Address correspondence to guoj@ufl .edu ABSTRACT We present a semi-analytical model incorporating the effects of edge bond relaxation, the third nearest neighbor interactions, and edge scattering in graphene nanoribbon fi eld-effect transistors (GNRFETs) with armchair-edge GNR (AGNR) channels. Unlike carbon nanotubes (CNTs) which do not have edges, the(More)
The expressions given in previous section, is for T = 0K. The room temperature results need to consider the Fermi distribution with integral over energy. The corresponding device parameters are labeled in the figures. A graphene length L = 100 nm is assumed. When the tunnel barrier is thicker, the resonant peak current decreases as expected (Figure 2 (a)).(More)
Tunneling field-effect transistors (FETs) have been intensely explored recently due to its potential to address power concerns in nanoelectronics. The recently discovered graphene nanoribbon (GNR) is ideal for tunneling FETs due to its symmetric bandstructure, light effective mass, and monolayer-thin body. In this work, we examine the device physics of(More)
Graphene has emerged as one of the most promising materials to address scaling challenges in the post silicon era. A simple model for graphene nanoribbon field-effect transistors (GNRFETs) is developed for treating the effects of edge bond relaxation, the third nearest neighbor interaction, and edge scattering, all of which are pronounced in GNRFETs, but(More)
A computationally efficient mode space simulation method for atomistic simulation of a graphene nanoribbon field-effect transistor in the ballistic limits is developed. The proposed simulation scheme, which solves the nonequilibrium Green’s function coupled with a three dimensional Poisson equation, is based on the atomistic Hamiltonian in a decoupled mode(More)
(Received 13 April 2012; accepted 9 July 2012; published online 20 July 2012) Ti/Al/Ni/Au ohmic contacts were formed on heavily doped nþ metal-polar GaN samples with various Si doping concentrations grown by molecular beam epitaxy. The contact resistivity (RC) and sheet resistance (Rsh) as a function of corresponding GaN free carrier concentration (n) were(More)
We explore the effects of metal contacts on the operation and scalability of 2-D graphene field-effect transistors (GFETs) using detailed numerical device simulations based on the nonequilibrium Green's function formalism self-consistently solved with the Poisson equation at the ballistic limit. Our treatment of metal-graphene (M-G) contacts captures the(More)
We report the realization of top-gated graphene nanoribbon field effect transistors (GNRFETs) of ~10 nm width on large-area epitaxial graphene exhibiting the opening of a band gap of ~0.14 eV. Contrary to prior observations of disordered transport and severe edge-roughness effects of GNRs, the experimental results presented here clearly show that the(More)
Compared to the intense research focus on the optical properties, the transport properties in non-polar and semi-polar III-nitride semiconductors remain relatively unexplored to date. The purpose of this paper is to discuss charge-transport properties in non-polar and semi-polar orientations of GaN in a comparative fashion to what is known for transport in(More)
The nonlinear characteristics of solid-state devices are widely used for high frequency applications such as mixers, detectors, and frequency multipliers; for example, the nonlinear rectifying behaviors of Schottky and heterostructure backward diodes are widely used for mixing and detection. Improved flexibility in device design while retaining a rectifying(More)