• 097513 - GRAPHENE NANOELECTRONICS AND NANOFABRICATION

The course is focused on the extraordinary physical properties of graphene (and related 2D materials) and their application in the development of nanoelectronic devices. The main goal of the course is to provide a comprehensive understanding of the physics of the state-of-the-art graphene electronic devices 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 nanofabrication methods used both in industry and research laboratories.

- Knowledge and understanding

The students will learn about the main physical properties of graphene and related two-dimensional (2D) materials and how they can be exploited to realize 2D electronic devices.

The students will learn about the state-of-the-art technologies for the fabrication of nanostructures and how they can be used to fabricate electronic devices at the nanoscale for applications in research and industry.

- Apply knowledge and understanding

The students will be able to extract important parameters and figures of merit of field-effect transistors (FETs) based on graphene and related 2D materials, both in dc and at high-frequencies.

The students will be able to evaluate the performance of FETs made of 2D and conventional semiconductor materials.

The students will be able to understand advantages and disadvantages of 2D FETs with respect to conventional Si transistor technology.

The students will be able to design a process flow for the fabrication of electronic devices at the nanoscale.

- Making judgements

The students will have the ability to compare different transistor technologies in terms of their applications in electronics.

The students will have the ability to select appropriate applications in electronics for FETs based on graphene and related 2D materials.

The students will have the ability to compare different nanofabrication techniques in terms of throughput, resolution, and possible applications in electronics.

- Lifelong learning skills

The students will be capable to autonomously learn how to use novel 2D and nanostructured materials in the development of transistors and electronic circuits.

The students will be capable to autonomously learn the features of new nanofabrication techniques.

The students will be prepared to begin a masters' thesis project in a semiconductor research laboratory.

Introduction to carbon-based material

• Allotropes and hybridization of carbon
• Band structure 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
• Methods for the synthesis of graphene

Graphene field-effect transistors (FETs)

• The importance of high carrier mobility in electronic devices and circuits
• Physics of graphene devices
• 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
• Related 2D materials (e.g., MoS₂)
• 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 g_m and output conductance g_d

Voltage and current gain

• Definition of voltage and current gains
• Intrinsic voltage gain g_m/g_d and intrinsic current gain h₂₁

High-frequency model of graphene FETs

• Extrinsic high-frequency model of FETs
• Phasors in electronic circuits
• Two-port networks
• h and Y parameter models of two-port networks

Cutoff frequency f_T of graphene FETs

• Cutoff frequency from Y parameters
• Intrinsic and extrinsic cutoff frequency f_T of graphene FETs
• Comparison of graphene and conventional FETs in terms of f_T

Power gain and maximum frequency of oscillation f_max of graphene FETs

• Definition of power gain
• Intrinsic and extrinsic maximum frequency of oscillation f_max of graphene FETs
• Comparison of graphene and conventional FETs in terms of f_max
• S parameters of two-port networks

Graphene electronic circuits

• Moore’s law
• Voltage gain and multi-stage circuits
• Noise margin
• Static and dynamic power dissipation
• Graphene electronic circuits: amplifiers, mixers, frequency multipliers, logic gates
• Realistic gate delays and graphene ring oscillators

Nanodevice Fabrication

• Introduction to lithography
• Deep ultraviolet lithography
• Resolution enhancement technologies
• Extreme ultraviolet lithography
• Electron beam lithography
• Alternative lithographic technologies
• Pattern transfer
• Nanofabrication of graphene nanoelectronic devices and circuits

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.

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 (i.e., single-transistor) electronic circuits with graphene, extract transistor parameters and determine corresponding figures of merit.