Photo of Kenneth Järrendahl

Kenneth Järrendahl

Professor, Head of Division, Head of Unit

Research

Most of my studies are focused on the use of polarized light to investigate structures on the nanometer scale. Often by using spectroscopic ellipsometry combined with other characterization methods such as electron microscopy and X-ray diffraction. The structures can be thin films, multilayers, superlattices, photonic crystals, sculpted films, and / or metamaterials. In most cases, they are artificially produced, but we have also done several studies of layered structures in beetle shells. It can also be added that I get extra excited if the structures are aperiodic or chiral.

I am head of the Materials Optics unit. Our research is fundamental, yet with a focus on finding and describing new optical phenomena that can be utilized in the future.

Teaching

I see teaching as an important part of my work and have therefore been involved in a variety of courses over the years. Nowadays, I am teaching courses related to Electromagnetics and Optics. I am also interested in pedagogy and have been involved in several educational projects. I also work with the institution's undergraduate educational administration.

What I am doing now

Research wise I am studying the polarization properties of helicoidal structures built of III-nitrides and at the same time trying to expand our knowledge of chiral beetle epicuticle. I am in the program committee for The 8th International Conference on Spectroscopic Ellipsometry (ICSE-8) taking place in Barcelona in May.
I am also preparing for my spring course in Optics and will invoke a new pedagogic approach I believe will make the topic (even more) exciting.

Publications

2026

Chih Yang Huang, Filip Gucmann, Anoop Kumar Singh, Po-Hsun Chen, Chien-Nan Hsiao, Edmund Dobrocka, Milan Tapajna, Igor Pis, Matej Micusik, Siddharth Rana, Dong-Sing Wuu, Po-Liang Liu, Kenneth Järrendahl, Ching-Lien Hsiao, Ray-Hua Horng (2026) Nano-scale Al redistribution at grain boundaries governs growth morphology in ß-(AlxGa1-x)2O3 on sapphire substrate via MOCVD DISCOVER NANO, Vol. 21, Article 325 (Article in journal) https://dx.doi.org/10.1186/s11671-026-04753-w
Yu-Hsuan Hsu, Roger Magnusson, Rohini Sanikop, Shailesh Kalal, Justinas Palisaitis, Sagar Jathar, Katrin Pingen, Per Sandström, Issa Nseir, Arnaud le Febvrier, Urban Forsberg, Ray-Hua Horng, Kenneth Järrendahl, Per Eklund, Vanya Darakchieva, Jens Birch, Ching-Lien Hsiao (2026) Growth and optical properties of polar-, nonpolar, and semi-polar wurtzite ScGaN films Applied Physics Letters, Vol. 129, Article 031902 (Article in journal) https://dx.doi.org/10.1063/5.0325421
Hans Arwin, Stefan Schoeche, Arturo Mendoza-Galvan, Kenneth Järrendahl, James N. Hilfiker, Roger Magnusson (2026) Transmission ellipsometry, circular birefringence, and circular dichroism in the Mueller-matrix formalism AIP Advances, Vol. 16, Article 065115 (Article in journal) https://dx.doi.org/10.1063/5.0314738
Zhong-Lin Ye, Siddharth Rana, Sheng-Ti Chung, Irmantas Kasalynas, Kenneth Järrendahl, Ching-Lien Hsiao, Ray-Hua Horng (2026) High-performance lateral ß-Ga2O3 Schottky barrier diodes enabled by (Al0.21Ga0.79)2O3/Ga2O3 heterostructure, sidewall electrodes, and dielectric field-plate engineering Results in Engineering (RINENG), Vol. 31, Article 111339 (Article in journal) https://dx.doi.org/10.1016/j.rineng.2026.111339
Chun-Chia Chang, Sheng-Ti Chung, Ching-Ho Tien, Siddharth Rana, Kenneth Järrendahl, Ching-Lien Hsiao, Yu-Chen Yang, Kun-Lin Lin, Irmantas Kasalynas, Ray-Hua Horng (2026) Enabled enhancement mode ß-Ga2O3 MOSFETs with high-? HfO2 gate dielectric and non-recess structure Materials Today Advances, Vol. 30, Article 100760 (Article in journal) https://dx.doi.org/10.1016/j.mtadv.2026.100760

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