84542 - SEMICONDUCTOR MATERIALS AND NANOSTRUCTURES

Course Unit Page

SDGs

This teaching activity contributes to the achievement of the Sustainable Development Goals of the UN 2030 Agenda.

Affordable and clean energy Industry, innovation and infrastructure

Academic Year 2020/2021

Learning outcomes

At the end of the course the student will learn the basic aspects of the physics of semiconducting materials, devices and interfaces, by studying in particular their transport and optical properties. He/she will be introduced also to quantum confinement effects in low dimensional systems and their application to optoelectronic and electronic devices.

Course contents

MODULE 1- 5 CFU (prof Cavalcoli):

Physics of semiconductors and low dimensional structures

  1. Semiconductor Physics. Elements of crystal structures, band structure and electronic levels of semiconductors. Ideal and Real crystals (role of defects, surfaces and interfaces). The chemical potential, Statistics. Transport properties, effective mass, current density, conductivity, generation- recombination mechanisms. Shockley Read Hall model. Optical properties of semiconductors.
  2. Surface and interface effects. Schottky model of metal-semiconductor devices. Metal Oxide Semiconductor structure and band diagram, MOS in strong inversion condition, introduction to quantum confinement effects.
  3. Quantum confinement in 2, 1 and 0 dimensions: Band gap engineering. Vergard’s law. quantum wells, wires and dots. Electrical and optical properties of low dimensional semiconductors. Growth and deposition of semiconductor nanostructures: methods and mechanisms.Quantum confinement effects in different confinement potentials. Rectangular potential wells and barriers. Harmonic oscillator. Particle in a spherically symmetric potential. Excitons in semiconductors at the nanoscale. Weak and strong quantum confinement effects. Influence on the optical properties. Investigation of semiconductor nanostructures by electrical, optical and microscopical methods.
  4. Applications of semiconductor nanostructures: Photovoltaic conversion. Advanced (3rd generation) solar cells.

Module 2 -1 CFU (Prof Bolognini)

Photonic applications: semiconductor-based opto-electronic sources (light-emitting diode –LED and LASER), photo-receivers (pin and avalanche photodiodes). Fundamentals on light generation and light sources for photonics, semiconductor photodiodes (pin and avalanche photodiodes, single photon detectors).

  1. Light/matter interaction. Optical absorption, spontaneous and stimulated emission, rate equations and Einstein coefficients in two-level systems and in semiconductors, population inversion
  2. Light emitting diode (LED). Spontaneous emission, the p-n junction, material properties, hetero-structures, lifetimes and quantum efficiency, LED characteristics and applications
  3. The LASER. Stimulated emission, cavity modes in Fabry-Pérot resonators, laser emission in semiconductors, hetero-structures, material gain and threshold, different types of laser, multi-quantum well and VCSEL lasers. Laser characteristics and applications
  4. Semiconductor photo-detectors. Optical absorption and quantum efficiency, spectral behaviour, p-i-n photodiodes, avalanche photodiodes.

Readings/Bibliography

Module 1

YU, Peter, Cardona, Manuel Fundamentals of Semiconductors: Physics and Materials Properties, Springer

Grundmann M. The Physics of Semiconductors, Springer

Tyagi M. Introduction of Semiconductor Physics and Devices, Wiley

M Jaros Physics and Applications of Semiconductor Microstructures, Oxford Science

J Davis The Physics of Low Dimensional Semiconductors, Cambridge University Press

Module 2

B.E.A. Saleh and M. C. Teich, Fundamentals of Photonics (John Wiley & Sons Editor), 2007

G.P. Agrawal, Fiber-Optic Communication Systems (John Wiley & Sons Editor), 2010

Yariv, A. Photonics: Optical Electronics in Modern Communications. 5th ed. New York, NY: Oxford University Press, 2007.

Svelto, O. Principles of Lasers. New York, NY: Springer-Verlag, 2004.

Review articles related to the main topics of the course will be uploaded on the platform https://iol.unibo.it/.

Teaching methods

Lectures. Group Discussion on Selected Topics.

Assessment methods

The assessment of the achievement of the learning outcomes is based on the following steps:

  • The student will prepare a report focused on one of the topics of the course where a recent literature research will be also presented. This report must be send by e-mail to the teacher 10 days before the oral exam date.
  • Oral exam: the assessment of the course learning outcomes will start from the topics of the student's report and will cover the main issues of the course.

The final score depends on the capability of the student in the presentation and/or critical analyses of the topics of the course.

Teaching tools

PC, projector, blackboard

Links to further information

https://iol.unibo.it/

Office hours

See the website of Daniela Cavalcoli

See the website of Gabriele Bolognini