ArchivIA Università degli Studi di Catania

ArchivIA - Archivio istituzionale dell'Universita' di Catania >
Tesi >
Tesi di dottorato >
Area 09 - Ingegneria industriale e dell'informazione >

Please use this identifier to cite or link to this item:

Issue Date: 10-Feb-2015
Authors: Fisichella, Gabriele
Title: Graphene Heterostructures with Wide Bandgap Semiconductors
Abstract: Graphene (Gr) is a two dimensional material constituted by an atomically thin carbon membrane, characterized by a unique combination of excellent electrical, optical, thermal and mechanical properties. Its main limitation for microelectronic applications is related to the lack of a bandgap, leading to a poor Ion/Ioff ratio when it is considered as channel material for MOSFET devices. Novel device concepts based on Gr heterostructures with semiconductors are currently under consideration, in order to overcome these limitations. These devices are based on the vertical current transport through Gr interfaces with semiconductors or thin insulators. Their working principle exploits some unique properties of Gr, such as the atomic thickness and the field effect modulation of its workfunction. Some demonstrations of these devices, recently reported in the literature, have been based on the integration of Gr with Si technology. This thesis work has been focused on the fabrication and the electrical characterization of high quality heterostructures of Gr with wide bandgap semiconductors (WBS), such as Silicon Carbide (4H-SiC), Gallium Nitride (GaN) and related alloys (AlxGa1-xN), which present superior properties for high power and high frequency electronic applications. At first, the fabrication methods have been discussed, i.e. (i) the controlled graphitization of the surface by high temperature thermal annealing, for 4H SiC; (ii) a highly reproducible transfer method to move Gr, grown by CVD on copper foils, to the surface of AlGaN/GaN heterostructures. A detailed structural, morphological and spectroscopic characterization of these Gr/WBS heterostructures has been carried out by the joint application of several analytical techniques, such as AFM; TEM, micro-Raman spectroscopy. Secondly, the current transport mechanisms through these heterostructures have been investigated in details by properly fabricated test devices and by nanoscale resolution electrical characterization techniques (CAFM, SCM). A correlation between the nanoscale structural, morphological and electrical properties of the interfaces with the devices average electrical behavior has been achieved. Basing on these results, some potential devices applications (such as the Gr/SiC Schottky diode with a gate modulated barrier and the hot electron transistor constituted by a Gr/AlGaN/GaN heterostructures with a Gr base) have been discussed and their advantages with respect to the Si counterparts have been estimated.
Appears in Collections:Area 09 - Ingegneria industriale e dell'informazione

Files in This Item:

File Description SizeFormatVisibility
FSCGRL87A05C351L-2014_12_05 Tesi Gabriele Fisichella.pdfGabriele Fisichella - tesi PhD, energetica XXVII ciclo9,78 MBAdobe PDFView/Open

Items in ArchivIA are protected by copyright, with all rights reserved, unless otherwise indicated.

Share this record




Stumble it!



  Browser supportati Firefox 3+, Internet Explorer 7+, Google Chrome, Safari

ICT Support, development & maintenance are provided by the AePIC team @ CILEA. Powered on DSpace Software.