• 097513 - GRAPHENE NANOELECTRONICS AND NANOFABRICATION

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 the course is to provide a comprehensive understanding of the state-of-the-art graphene high-frequency 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 the electronic devices at the nanoscale providing the comprehensive understanding of the fabrication methods used both in industry and research laboratories.

The 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.

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 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

Cutoff frequency f_T of graphene FETs

• Intrinsic and extrinsic cutoff frequency f_T of graphene FETs
• Comparison of graphene and conventional FETsin terms of f_T
• h and Y parameter models of two-port networks
• Cutoff frequency from Y parameters

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 FETsin terms of f_max
• S parameters of two-port networks

Graphene electronic circuits

• Graphene 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 electronic circuits with graphene, extract transistor parameters and determine corresponding figures of merit.