Terahertz RF Transistor Technology Based on Graphene and GaN Channel Materials System
General Material Designation
[Thesis]
First Statement of Responsibility
Nazir Hossain, Abu Hena Muhammad
Subsequent Statement of Responsibility
Margala, Martin
.PUBLICATION, DISTRIBUTION, ETC
Name of Publisher, Distributor, etc.
University of Massachusetts Lowell
Date of Publication, Distribution, etc.
2020
PHYSICAL DESCRIPTION
Specific Material Designation and Extent of Item
80
DISSERTATION (THESIS) NOTE
Dissertation or thesis details and type of degree
Ph.D.
Body granting the degree
University of Massachusetts Lowell
Text preceding or following the note
2020
SUMMARY OR ABSTRACT
Text of Note
In recent years, there is growing interest in the research and development of solid state-based Terahertz (THz) devices and applications. Within the last two decades, THz applications have become more and more important in various areas such as medical imaging, biological and genomic studies, security screening, pharmaceutical industry, industrial quality control, atmospheric/space studies and so on. As the frequency gets into the Terahertz region, it is able to lead the communication systems with much higher data rates. In my research work, I studied the graphene and III-nitride based device structure to explore the feasibility of terahertz electronic device system. Graphene has regarded as an ideal candidate channel material for the radio frequency flexible electronics. Graphene is one of emerging electronics material which has highest carrier mobility, high saturation velocity, high critical current densities, and single atom thick layered with the highest projected cut-off frequency around 1-30 THz. However, the fabrication process of THz graphene transistor is extremely challenging due to the undesirable defect into the graphene lattice. In this novel work, we present the experimental result of electric field distribution of in-plane graphene structure by investigating the IV-CV measurements at room temperature. In addition, we studied the Raman spectroscopy at 532nm, and correlative analysis of energy selective backscattered electrons mapping taken by ESB detector and the secondary electrons image acquired by the In-Lens detector at different energy level to confirm the graphene layer present on specific location and the layer thickness. The experimental results show that the capacitance coupling between two electrodes is 450 fFmm-1 at 0.18V potential difference. The in plane gated transistor based of GaN/SiC provide better RF performances. For the first time, I developed in plane transistor technology which provide broad transconductance to ensure the higher linear operation frequency range from 90GHz to 250GHz. In my investigation, I have shown that for the GaN/SiC in plane technology can provide sufficient output power 30dBm at third order intercept point.