Closing Date: March 31, 2006

The Photonics Laboratory at Chalmers University of Technology, Göteborg, Sweden, has a PhD student position open for work on semiconductor lasers and related material studies. The research area is described below.

Dilute nitride materials and lasersDilute nitrides (such as GaInNAs) are created by adding a small amount of N to ordinary III-V semiconductor compounds. The incorporation of N results in unique material properties, such as a significant reduction of the bandgap. This enables an emission wavelength of 1.3 µm to be reached by materials grown on GaAs substrates and also provides deep potential wells for injected carriers and therefore improved laser performance at high temperature. This is of importance for applications where cost is a critical issue, such as in fiber optical access networks.

The work at Chalmers targets high performance 1.3 µm GaInNAs lasers on GaAs substrates (both edge emitters and vertical cavity surface emitting lasers), including epitaxial growth, basic material studies, and laser design, fabrication, and evaluation.

Layered material and laser structures are grown in-house by molecular beam epitaxy (MBE) using an RF-coupled plasma source for evaporation of atomic N. Growth conditions are optimized for high radiative efficiency and favorable optical gain characteristics, ultimately leading to high performance lasers.

Materials are studied using techniques such as photo-luminescence, X-ray diffraction, and transmission electron microscopy with the aim of improving the understanding of basic material properties and providing feedback for improved growth.

Semiconductor lasers are fabricated from material grown by MBE using our nanofabrication facility. Lasers are characterized in terms of their static and dynamic characteristics, including e.g. threshold current, efficiency, spectral characteristics, modulation bandwidth, noise, and impedance characteristics. The modulation characteristics are studied at high bit rates. Special attention is given to the temperature dependence of all these parameters.

We seek a PhD student with a Master degree in Electrical Engineering or Applied Physics (or an equivalent degree), preferably with a sound knowledge in solid state physics, electromagnetics, and optoelectronics. Experience in any of the areas of device fabrication, design/simulations, laser evaluation (including high frequency measurements), and opto-mechanical assembly would be an important merit.

For further information, please contact:
Professor Anders Larsson,
+46-31-7721593,
anders.larsson@mc2.chalmers.se

Professor Shumin Wang,
+46-31-7725039,
shumin.wang@mc2.chalmers.se

Welcome with your application, which may be submitted by e-mail, containing: application letter, CV, exam with grades, contact details of at least two references and your MSc thesis.

Send your expression of interest quoting reference number 20/2006, by March 31, 2006 to:
Registrar
Chalmers University of Technology
SE-412 96 Göteborg, Sweden
Phone exch: +46 31 772 10 00
Fax registrar: +46 31 772 49 22
e-mail: registrator@chalmers.se