Optics of Solid-state Nanostructures (Spring 2010)


Overview

This course focuses on semiconductor nanostructures, e.g. quantum wells (QWs) and quantum dots (QDs), and their optical properties. We will be discussing the ways in which modern crystal growth and processing techniques are used to create low-dimensional systems for the study of quantum mechanics, spin physics, and for device engineering. In addition, we will highlight optical methods for investigating these systems. The course will start by coving some fundamental concepts and build up to review state-of-the-art experiments.

The main topics to be covered include: band structure, optical absorption and emission, optical selection rules, band engineering, heterostructure growth, QWs, QDs, excitons, spin injection and polarized excitation/detection, Hanle effect, Faraday effect, dynamic nuclear polarization, optically detected magnetic resonance, paramagnetic and ferromagnetic semiconductors, spintronics and applications, and photonic band-gap devices.


Format and Requirements

The course consists of one 2-hour lecture per week and one 1-hour exercise session per week. Exercise sessions will be a forum for in depth discussion of relevant papers, assigned exercises, and general questions. A final report on an important experimental paper is required (4-5 pages or 3000-5000 words). The course will be conducted in English. The grading is pass/fail.

This course will be aimed at 3rd-year bachelor and master students in physics and nanoscience. Physics III is a prerequisite. Previous course-work in solid-state physics and quantum mechanics is expected.

Most of the source material and reading in this class will be drawn from The Physics of Low-dimensional Semiconductors, J. H. Davies (Cambridge University Press, 1998. Some reading will be based on short sections of Fundamentals of Semiconductors, P. Y. Yu and M. Cordona (Springer, 2005); Wave Mechanics Applied to Semiconductor Heterostructures, G. Bastard (Les Editions de Physique, 1988); Optical Orientation, F. Meier and B. P. Zakharchenya (North-Holland, 1984); and from original papers in scientific journals. Copies of these readings will be distributed in class.


Schedule


Lectures: Wednesdays, 14.00-16.00, Sitzungszimmer 1.09
Exercise Sessions: Thursdays, 15:00-16:00, Sitzungszimmer 3.12
Date Lecture Content
02.03.2010 Preliminary Logistics & Introduction
Course outline and expectations. What are solid-state nanostructures? Why use optics to study them? Basic concepts of quantum and statistical physics.

Exercise Session: CANCELED

Reading: The Physics of Low-dimensional Semiconductors, chp. 1.

Downloads: Lecture slides, Exercise sheet 1.
10.03.2010 Band Structure I
Band structure. Formation of band-gaps. Conduction and valence bands. Crystal structure of common semiconductors. k·p approximation.

Exercise Session: Complete exercise sheet 1 before the session.

Reading: The Physics of Low-dimensional Semiconductors, chp. 2.

Downloads: Lecture slides, Lecture notes, Exercise sheet 2.
17.03.2010 Band Structure II
Band calculation for the III-V compound GaAs. Nearly free electron model. Kane model. Spin-orbit coupling.

Exercise Session: Complete exercise sheet 2 before the session.

Reading: The Physics of Low-dimensional Semiconductors, sec. 7.2, 7.3, 7.6, 7.8, and 10.2.

Downloads: Lecture notes.
24.03.2010 Heterostructures
Growth of heterostructures. Band engineering. Quantum wells and barriers. Doping. Strain. Wires and dots.

Exercise Session: Complete exercise sheet 3 before the session.

Reading: The Physics of Low-dimensional Semiconductors, chp. 3.

Downloads: Lecture slides, Lecture notes, Exercise sheet 4.
31.03.2010 Quantum Wells
Various types of quantum wells. Other low-dimensional systems. Sub-bands. Real quantum wells in heterostructures.

Exercise Session: Holiday.

Reading: The Physics of Low-dimensional Semiconductors, chp. 4.

Downloads: Lecture slides, Lecture notes.
07.04.2010 LECTURE CANCELED
There will be no lecture this week.

Exercise Session: Complete exercise sheet 4 before the session.

Reading: The Physics of Low-dimensional Semiconductors, chp. 4.

Downloads: None.
14.04.2010 LECTURE CANCELED
There will be no lecture this week.

Exercise Session: CANCELED.

Reading: None.

Downloads: None.
21.04.2010 Optical Excitation (Prof. Richard Warburton)
Optical absorption. Interband absorption. Absorption in a quantum well. Excitons.

Exercise Session: CANCELED.

Reading: The Physics of Low-dimensional Semiconductors, chp. 8, 10; Wave Mechanics Applied to Semiconductor Heterostructures, chp. 7.

Downloads: Exercise sheet 5.
28.04.2010 Optical Orientation I
Excitation with circularly polarized light. Selection rules. Electron spin precession and relaxation. The Hanle effect. The Faraday effect. Optical measurements of spin.

Exercise Session: Complete exercise sheet 5 before the session.

Reading: Optical Orientation, chp. 1, 2.

Downloads: Lecture slides, Lecture notes.
05.05.2010 Optical Orientation II
Contact hyperfine coupling. Dynamic nuclear polarization. Optically detected magnetic resonance. Conduction band coupling to other types of localized moments.

Exercise Session: Complete exercise sheet 5 before the session.

Reading: Optical Orientation, chp. 1, 2.

Downloads: Lecture notes.
12.05.2010 HOLIDAY
There will be no lecture this week.

Exercise Session: HOLIDAY.

Reading: None.

Downloads: None.
19.05.2010 Quantum Dots
Lithographically defined dots. Chemically synthesized dots. Epitaxially grown dots. Fluctuation dots. Optical and electronic properties.

Exercise Session: Complete exercise sheet 6 before the session.

Reading: None.

Downloads: Lecture slides, Lecture notes.
26.05.2010 Semiconductor Lasers
Threshold. Photon statistics. Linewidth. Devices and engineering. The quantum cascade laser.

Exercise Session: CANCELLED.

Reading: None.

Downloads: Lecture slides.
02.06.2010 Paper Presentations
Each student will present a 5-minute abstract of his/her final paper to the class. See the list of suggested publications below.



References

  • The Physics of Low-dimensional Semiconductors, J. H. Davies (Cambridge University Press, 1998).

  • Fundamentals of Semiconductors, P. Y. Yu and M. Cordona (Springer, 2005).

  • Wave Mechanics Applied to Semiconductor Heterostructures, G. Bastard (Les Editions de Physique, 1988).

  • Optical Orientation, F. Meier and B. P. Zakharchenya (North-Holland, 1984).


Suggested Publications for Reports

  • Optically programmable electron spin memory using semiconductor quantum dots, M. Kroutvar et al., Nature 432, 81 (2004).