Optics of Semiconductors and their Nanostructures

This course will provide the student with an in-depth understanding of the optical properties of bulk semiconductors, semiconductor heterostructures and their nanostructures. We will concentrate on key materials, usually tetrahedrally coordinated materials such as group IV elements Si and Ge, the III-V compound semiconductors such as GaAs, the IIb-VI semiconductors such as CdS, ZnO or ZnSe, the Ib-VII materials such as the Cu halides and hexagonally coordinated materials such as grou-III nitrides, transition metal dichalcogenides and graphene. Our aim will be to connect fundamental physics with the practicalities of modern spectroscopic methods. We will explore the impact of external magnetic, electric and strain fields on the optical response of semiconductor materials and discuss bulk and microcavity exciton polaritons, for which Bose-Einstein condensation was observed a little over a decade ago. This will provide the student with an understanding for how advanced photonic devices, nanolasers and tailored optical non-linearities can possibly be used for future, all optical, routes towards information processing.

Introduction and Review (1-lecture)
• Maxwell’s equations in matter, linear optical response
• Boundary conditions and Fresnel’s formulae
• Birefringence, dichroism and optical activity

Experimental techniques for optical spectroscopy (2-lectures)
• Emission and excitation methods
• Excitation sources
• Monochromators, Spectrographs and Detectors
• Fourier Transform Spectroscopy

Kinetic description of luminescence processes (1-lecture)
• Radiative and non-radiative recombination, quantum yield
• Mono-molecular and bimolecular processes

Quasiparticles (Excitons, Biexcitons and Trions – 2 lectures)
• Wannier and Frenkel Excitons
• Impact of dimensionality (Excitons in Quantum Wells, Wires and Dots)
• Biexcitons and Trions
• Bound exciton complexes
• Excitons in disordered systems

Participation of lattice vibrations (2-lectures)
• Electron-Phonon interactions
• Reflection, Raman and Brillouin scattering
• Participation of phonons in optical processes
• Phonons in alloys and localized modes at defects and surfaces
• Phonon dynamics

High-excitation effects and non-linear optics (2-lectures)
• Beyond linear susceptibility
• Key chi(2) and chi(3) processes
• Intermediate density regime (two-photon processes, X-X interactions)
• Optical or AC Stark effect
• Excitonic Bose-Einstein Condensation
• Electron-Hole Plasma

Stimulated emission and laser processes (2-lectures)
• Excitonic Processes
• Electron-Hole Plasmas
• Cavity and Random lasing
• Stimulated emission in low-dimensional structures
• Silicon nano photonics and current-trends

Time-resolved and coherent spectroscopy methods (2-lectures)
• Basic Time Constants
• Decoherence and Phase Relaxation
• Quantum Coherence, Coherent Control and Non-Markovian Decay
• Transport Properties
• Interband Recombination
• Four-Wave and Six-Wave Mixing

After attending this MSc level course, the student will obtain an in-depth understanding of the optical properties of semiconductors, such as the spectrum of optical transmission, reflection and luminescence or, alternatively, the complex dielectric function spanning the entire optical regime from the infrared, through the visible to the near-ultraviolet region of the electromagnetic spectrum.

No preconditions in addition to the requirements for the Master’s program in Physics.

Class Lecture (2 SWS per week) combined with 1 SWS (Exercises, Tutorial, Practical Discussion)

Frontal presentation, e-media, PPT and videos.

Optical Properties of Solids, A. M. Fox. Oxford Master Series in Physics, (2010)

Semiconductor Optics, C. F. Klingshirn, 4th Edition, Springer (2012)

Microcavities, A. V. Kavokin, J. J. Baumberg, G. Malpuech and F.P. Laussy, Oxford University Press (2012)

In a written exam of 60 minutes the learning outcome is tested using comprehension questions and sample problems.

In accordance with §12 (8) APSO the exam can be done as an oral exam. In this case the time duration is 25 minutes.