Ing Ind - Inf (Mag.)(ord. 270) - MI (486) ENGINEERING PHYSICS - INGEGNERIA FISICA
097516 - GRAPHENE AND NANOELECTRONIC DEVICES [I.C.]
097607 - NANODEVICE FABRICATION AND CHARACTERIZATION
097606 - GRAPHENE NANOELECTRONICS
As modern technology moves ever further into the nanoscale, it becomes essential to extend fundamental solid-state physics knowledge to systems of reduced dimensionality. The tools developed to understand charge transport in high mobility 2-dimensional systems, such as semiconductor heterostructures and graphene, focus on the behaviour of electrons in solids in electric and magnetic fields. The study of the rich physics seen in these systems at low temperatures and high magnetic fields allows an understanding to be developed of state-of-the-art devices operating under everyday conditions, which is fundamental to the development of future technology.
Details of the first part of the integrated course are given on the "Nanodevice Characterization" page.
The second part of the course is focused on the extraordinary physical properties of graphene and their application in the development of graphene nanoelectronic devices. The main goal of this part of the course is to provide a comprehensive understanding of the state-of-the-art graphene ultrafast electronics and realistically evaluate possible applications of graphene in modern electronics. The course also presents the state-of-the-art methods for the fabrication of electronic devices at the nanoscale providing the comprehensive understanding of the fabrication methods used both in industry and research laboratories.
Details of the second part of the integrated course are given on the "Graphene Nanoelectronics and Nanofabrication" page.
Risultati di apprendimento attesi
Following the Nanodevice Characterization course, the student understands the main physical phenomena relevant to low-dimensional semiconductor structures and devices, and how to recognise and evaluate these phenomena in terms of their manifestation in experimental results.
The student understands how to extract important parameters and figures of merit from experimental transport data, and how to design experiments which can measure these data.
The student understands the main structural characterization methods used for semiconductor materials.
Follwoing the Graphene Nanoelectronics and Nanofabrication student understands:
the main physical properties of graphene and how they can be exploited to realize graphene electronic devices;
how to extract important parameters and figures of merit of graphene field-effect transistors (GFETs) both in dc and at high-frequencies;
the advantages and disadvantages of GFETs with respect to conventional Si transistor technology;
the suitable applications of graphene in electronics;
the state-of-the-art technologies for the fabrication of devices at the nanoscale, both used in research and industry.
Linear transport theory: scattering mechanisms and screening, quantum and transport lifetimes.
The Boltzmann equation: relaxation time approximation, electrical and thermal conductivity and thermoelectric processes.
2-dimensional carrier gases: ballistic transport, high electron mobility transistors.
Weak magnetic fields at low temperature: weak localization.
Strong magnetic fields at low temperature: Landau levels, Shubnikov-de Haas oscillations, and the quantum Hall effect.
Strong magnetic fields at room temperature: parallel conduction channels and the mobility spectrum.
Vertical transport devices: the transfer matrix treatment of resonant tunnel diodes.
Methods of obtaining physical and structural information at the nanoscale: X-ray diffraction of thin films; High-resolution x-ray diffraction; Nanofocused x-ray beams at synchrotron light sources; Raman and micro-Raman spectroscopy in semiconductors; Tip-enhanced Raman spectroscopy; Micro-photoluminescence.
Graphene Nanoelectronics and Nanofabrication:
Introduction to carbon-based material
Allotropes and hybridization of carbon
Band spectrum and massless Dirac fermions in graphene
The origin of high charge carrier mobility in graphene
Comparison with carbon nanotubes
Klein paradox and half-integer quantum Hall effect
Graphene field effect transistors (FETs)
The importance of high mobility in electronic devices and circuits
Comparison between graphene and conventional FETs
Ambipolarity of graphene FETs
Electrostatic doping in graphene electronic circuits
The importance of drain current saturation and voltage gain
Impact of contact resistance on the properties of graphene FETs
Scaling and short-channel effects
Impact of band gap opening in graphene on FET properties
Small-signal model of graphene FETs
Low-frequency AC small signal model of FETs (hybrid-pi model)
Determination of transconductance gm and output conductance gd
Voltage and current gain
Definition of voltage and current gains
Intrinsic voltage gain gm/gd and intrinsic current gain h21
High-frequency model of graphene FETs
Extrinsic high-frequency model of FETs
Phasors in electronic circuits
Cutoff frequency fT of graphene FETs
Intrinsic and extrinsic cutoff frequency fT of graphene FETs
Comparison of graphene and conventional FETsin terms of fT
h and Y parameter models of two-port networks
Cutoff frequency from Y parameters
Power gain and maximum frequency of oscillation fmax of graphene FETs
Definition of power gain
Intrinsic and extrinsic maximum frequency of oscillation fmax of graphene FETs
Comparison of graphene and conventional FETsin terms of fmax
S parameters of two-port networks
Graphene electronic circuits
Graphene Moore’s law
Voltage gain and multi-stage circuits
Static and dynamic power dissipation
Graphene electronic circuits: amplifiers, mixers, frequency multipliers, logic gates
Realistic gate delays and graphene ring oscillators
Introduction to lithography
Deep ultraviolet lithography
Resolution enhancement technologies
Extreme ultraviolet lithography
Electron beam lithography
Alternative lithographic technologies
Nanofabrication of graphene nanoelectronic devices and circuits
For Nanodevice Characterization the student will benefit from having already completed some courses in solid-state physics, for example Solid State Physics (096033) and Physics of Surfaces (096056).
For Graphene Nanoelectronics and Nanofabrication the student will benefit from having already completed some courses in solid-state physics, for example Solid State Physics (096033) and Electronics (096032). However, this is not obligatory.
Modalità di valutazione
For Nanodevice Characterization the student will be evaluated by oral examination according to the calendar of the course.
The student will be expected to discuss the physical phenomena which give rise to certain results or experimental effects, and what information regarding the characterization of the sample or device under test can be extracted from the experimental results. Emphasis is placed on the comprehension of real experimental data rather than calculation of simplified systems or reproduction of text-book derivations.
For Graphene Nanoelectronics and Nanofabrication the student will be evaluated by written examination according to the calendar of the course. The student will be expected to discuss the physical phenomena underlying applications of graphene in electronics, solve basic electronic circuits with graphene, extract transistor parameters and determine corresponding figures of merit.
Luis E. F. Foa Torres, Stephan Roche, Jean-Christophe Charlier, Introduction to Graphene-Based Nanomaterials - From Electronic Structure to Quantum Transport, Anno edizione: 2014, ISBN: 9781107030831
Juin J. Liou, Frank Schwierz, Hei Wong, Nanometer CMOS, Anno edizione: 2010, ISBN: 9814241083
Zheng Cui, Nanofabrication - Principles, Capabilities and Limits, Anno edizione: 2008, ISBN: 978-0-387-75576-2
Neil W. Ashcroft and N. David Mermin, Solid State Physics, Editore: Thomson Learning
J. H. Davies, The Physics of Low-Dimensional Semiconductors, Editore: Cambridge University Press, Anno edizione: 1998
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