Graphene Transistor Based Nanoelectronic and Nanophotonic Applications.

Abstract

Over the past few decades, electronics and photonics have made significant impacts on every aspect of our daily life. Importantly, as the technology advancing and moving forward, the development of these devices not only relies on deeper fundamental understanding but also requires novel materials with unique properties as well as new device architecture to achieve higher performance with more diverse functionalities. In this regards, low dimensional materials inherently possess properties that are conceptually different from those of bulk materials in most aspects. The capability to tailor these nanomaterials as well as their unique properties is essential to achieve unconventional devices with revolutionary impacts. In this dissertation work, our aim is to develop novel nanoelectronics and nanophotonics by exploiting the extraordinary characteristics of purely two-dimensional (2D) monolayer graphene and its heterostructures. Firstly, we design and propose the dual-gate graphene ambipolar transistor that can operate as either common mode or differential mode amplifier by properly tuning the gate biases. Our device can also achieve high noise rejection amplification with common mode rejection ration (CMRR) as high as 80 dB, which is comparable to a commercial operational amplifier (op-amp). Secondly, we demonstrate the hyperbolic metamaterials (HMMs) by using precisely controlled periodic graphene-dielectric multilayer nanostructures to investigate the optical topological transition from elliptical to hyperbolic dispersion in mid-infrared regime. Thirdly, we propose the graphene-SOI heterojunction broadband photodetector design to improve the device on-off operation speed, strengthen the photo-gating effect, as well as minimize the dark current. We further fabricate the single pixels into 32 x 32 matrix arrangement to demonstrate the proof-of-concept image array readout, opening up the development of graphene-based ultra-broadband image sensor array applications. Lastly, we propose the all-graphene transparent photodetector design for light-field imaging and demonstrate the proof-of-concept one-dimensional (1D) ranging by using two stacked single-pixel transparent photodetectors. The results should lay the stepping stones and foundation for the new generation of graphene-based light-field photodetectors and image sensors.