Semiconductor Physics
A.Y. 2024/2025
Learning objectives
The course provides fundamentals for the understanding of the microscopic properties of relevant topics of Physics of Semiconductors and of their applications. Special focus will be given on:
1.Understanding the electronic, vibrational, optical and magnetic properties of semiconductors
2.Defects (shallow and deep)
3.Transport in 3D semiconductors
4.Electronic properties and transport in nanostructures 2D, 1D, 0D
5.Physics of heterostructures and junctions: basic concepts for understanding nanoelectronic devices
1.Understanding the electronic, vibrational, optical and magnetic properties of semiconductors
2.Defects (shallow and deep)
3.Transport in 3D semiconductors
4.Electronic properties and transport in nanostructures 2D, 1D, 0D
5.Physics of heterostructures and junctions: basic concepts for understanding nanoelectronic devices
Expected learning outcomes
Skills acquired by the student at the end of the course:
1. Description of microscopic mechanisms responsible of transport properties in semiconductors
2. Knowledge of main growth and characterization techniques used for semiconductors
3. Knowledge of principal computational techniques used for semiconductors
4. Description of quantum confinement effects in semiconductor nanostructures.
5. Knowledge of main processes governing the physics of semiconductors. Application of skills acquired in the course to made research and development of semiconductor technology in academy or in industry.
1. Description of microscopic mechanisms responsible of transport properties in semiconductors
2. Knowledge of main growth and characterization techniques used for semiconductors
3. Knowledge of principal computational techniques used for semiconductors
4. Description of quantum confinement effects in semiconductor nanostructures.
5. Knowledge of main processes governing the physics of semiconductors. Application of skills acquired in the course to made research and development of semiconductor technology in academy or in industry.
Lesson period: First semester
Assessment methods: Esame
Assessment result: voto verbalizzato in trentesimi
Single course
This course can be attended as a single course.
Course syllabus and organization
Single session
Responsible
Lesson period
First semester
Course syllabus
The purpose of the course is the illustration of basic concepts of Physics of Semiconductors. During the class the main simulation methods and experimental techniques for the study of semiconductor physics will be introduced; the industrial applications and recent development of new materials for ultra-scaled electronics will be mentioned.
Topics:
1. Introduction to growth techniques for semiconductors (2).
MOCVD, MBE, ALD techniques.
2. Crystal structures (1).
Crystal structures; Bravais lattices; spatial point groups; reciprocal lattice; Miller indexes.
3. Energy bands (3).
Bloch states; Wannier functions; tight binding method; pseudo-potential techniques; kp approximation; valence and conduction bands; spin-orbit interaction; definition of effective mass and its experimental measurement.
4. Phonons and thermal properties in semiconductors and materials for nano-electronics (4).
Phonon branches; theoretical models; experimental techniques.
5. Defects in semiconductors: structural, electronic and vibrational properties (4).
Point defects; doping agents; impurities; complexes. Shallow defects: effective mass theory. Deep defects: Green functions.
6. Equilibrium distribution (4).
Statistics of carriers; thermodynamics; density of states; electron and hole distribution; intrinsic and extrinsic semiconductors; Fermi level; chemical potential.
7. Optical properties (4).
Electron-photon interaction: polaritons. Infra-band absorption, inter-band absorption; excitons, free-carrier absorption. Reflectivity. Kramers-Kronig relations. Photon scattering: Raman spectroscopy. Photoluminescence. Photoionization.
8. Transport properties (4).
Macroscopic quantities. Boltzmann equation; distribution function; charge transport; scattering processes, relaxation time; Hall effect; magnetoresistance; high field effects; hot carriers, Gunn effect.
9. Excess carriers (2).
Generation and recombination. Drift and diffusion. Thermodynamic equilibrium junctions. Non-equilibrium junctions.
10. Berry phase (2). Polarization in semiconductors; quantum Hall effect.
11. Heterostructures (4).
Space charge region; impact ionization; tunnel effect; two-dimensional electron gas. Transport. Quantum Hall effect.
12. Solar Cells (2).
Photovoltaic effect; solar cell efficiency; solar cells of first, second, and third generation; commercial issues.
13. Nanostructures. (2)
Quantum well. 1D e 0D structures; Coulomb blockade. Single electron devices.
14. Spintronics (2).
Introduction to spin electronics. Rashba effect; spin transistor; magnetic semiconductors; Heusler compounds.
15. Quantum computer (2).
Proposals for a quantum computer; Kane's architecture.
Topics:
1. Introduction to growth techniques for semiconductors (2).
MOCVD, MBE, ALD techniques.
2. Crystal structures (1).
Crystal structures; Bravais lattices; spatial point groups; reciprocal lattice; Miller indexes.
3. Energy bands (3).
Bloch states; Wannier functions; tight binding method; pseudo-potential techniques; kp approximation; valence and conduction bands; spin-orbit interaction; definition of effective mass and its experimental measurement.
4. Phonons and thermal properties in semiconductors and materials for nano-electronics (4).
Phonon branches; theoretical models; experimental techniques.
5. Defects in semiconductors: structural, electronic and vibrational properties (4).
Point defects; doping agents; impurities; complexes. Shallow defects: effective mass theory. Deep defects: Green functions.
6. Equilibrium distribution (4).
Statistics of carriers; thermodynamics; density of states; electron and hole distribution; intrinsic and extrinsic semiconductors; Fermi level; chemical potential.
7. Optical properties (4).
Electron-photon interaction: polaritons. Infra-band absorption, inter-band absorption; excitons, free-carrier absorption. Reflectivity. Kramers-Kronig relations. Photon scattering: Raman spectroscopy. Photoluminescence. Photoionization.
8. Transport properties (4).
Macroscopic quantities. Boltzmann equation; distribution function; charge transport; scattering processes, relaxation time; Hall effect; magnetoresistance; high field effects; hot carriers, Gunn effect.
9. Excess carriers (2).
Generation and recombination. Drift and diffusion. Thermodynamic equilibrium junctions. Non-equilibrium junctions.
10. Berry phase (2). Polarization in semiconductors; quantum Hall effect.
11. Heterostructures (4).
Space charge region; impact ionization; tunnel effect; two-dimensional electron gas. Transport. Quantum Hall effect.
12. Solar Cells (2).
Photovoltaic effect; solar cell efficiency; solar cells of first, second, and third generation; commercial issues.
13. Nanostructures. (2)
Quantum well. 1D e 0D structures; Coulomb blockade. Single electron devices.
14. Spintronics (2).
Introduction to spin electronics. Rashba effect; spin transistor; magnetic semiconductors; Heusler compounds.
15. Quantum computer (2).
Proposals for a quantum computer; Kane's architecture.
Prerequisites for admission
Basic knowledge of quantum mechanics and basic concepts of the structure of matter
Teaching methods
During the lesson the topics are also illustrated by examples, citing the uses of semiconductor materials in the microelectronics industry, and with discussions to provide an in-depth understanding of the most relevant ideas and methods.
Teaching Resources
M. Balkanski and R. F. Wallis, Semiconductor Physics and applications, (Oxford University Press, 2000); P. Yu and M. Cardona Fundamentals of Semiconductors (Springer 2010); Lectures notes. References about specific topics can be provided during the lessons.
Assessment methods and Criteria
The exam consists of an interview typically lasting 30-40 minutes in which the student must illustrate the topics of the program.
Importance is assigned to the understanding of ideas and methods relevant for the study of the physical properties of semiconductors
Importance is assigned to the understanding of ideas and methods relevant for the study of the physical properties of semiconductors
Educational website(s)
Professor(s)