Modeling of a Graphene Nanoribbon–based Microfluidic Surface Plasmon Resonance Biosensor

A surface plasmon resonance (SPR) biosensor based on a graphene nanoribbon array in a microfluidic flow cell operating in a flow-over format is studied. The optical response of the biosensor is numerically obtained by using rigorous couple wave analysis (RCWA). The performance of the biosensor is described in terms of the limit of detection, which is calculated as a function of key nanoribbon dimensional parameters, such as strip thickness and width, and fill fraction (nanoribbon width to array period ratio). The analysis shows that there are specific values of the fill fraction that optimize, that is, minimize, the limit of detection for particular nanoribbon dimensions. Fabrication issues are also discussed. This study is expected to assist in the design and implementation of SPR biosensors based on nanopatterned 2D materials.

Performance enhancement of armchair graphene nanoribbon resonant tunneling diode using V-shaped potential well

We study the electron transport in armchair graphene nanoribbon (AGNR) resonant tunneling diode (RTD) using square and V-shaped potential well profiles. We use non-equilibrium Green’s function formalism to analyze the transmission and I-V characteristics. Results show that an enhancement in the peak current (Ip ) can be obtained by reducing the well width (Ww ) or barrier width (Wb ). As Ww decreases, Ip shifts to a higher peak voltage (Vp ), while there is almost no change in Vp with decreasing Wb . It is gratifying to note that there is an enhancement in Ip by about 1.6 times for a V-shaped well over a square well. Furthermore, in the case of a V-shaped well, the negative differential resistance occurs in a shorter voltage range, which may beneficial for ultra-fast switching and high-frequency signal generation. Our work anticipates the suitability of graphene, having better design flexibility, to develop ideally 2D RTDs for use in ultra-dense nano-electronic circuits and systems.