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

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) Continue to DOI
Marcus Lorentzon, Kenneth Järrendahl, Roger Magnusson, Jens Birch, Naureen Ghafoor (2026) Hf1-xAlxNy: A versatile material system for visible-range anti-reflection and high-reflection optical coatings Materials Today Communications, Vol. 52, Article 114960 (Article in journal) Continue to DOI
Chun-Chia Chang, Sheng-Ti Chung, Siddharth Rana, Kenneth Järrendahl, Ching-Lien Hsiao, Ray-Hua Horng (2026) Performance study of non-recess structure for ß-Ga2O3 MOSFETs applications Results in Engineering (RINENG), Vol. 29, Article 108757 (Article in journal) Continue to DOI

2025

Ching-Hsuan Lee, Sheng-Ti Chung, Chien-Nan Hsiao, Po-Hsun Chen, Po-Liang Liu, Kenneth Järrendahl, Ching-Lien Hsiao, Ray-Hua Horng (2025) Substrate Off-Cut Effect on the Performance of Enhancement-Mode ß-Ga2O3 Metal-Oxide-Semiconductor Field-Effect Transistors ACS Applied Electronic Materials, Vol. 7, p. 11229-11239 (Article in journal) Continue to DOI
Shailesh Kalal, Martin Magnuson, Alessandro Chesini, Akshaya A, Sanath Kumar Honnali, Sophia Sahoo, Nakul Jain, Dibyendu Bhattacharyya, Andrei Gloskovskii, Mukul Gupta, Feng Wang, Michele Orlandi, Grzegorz Greczynski, Kenneth Järrendahl, Per Eklund, Jens Birch, Ching-Lien Hsiao (2025) Defect Engineering in Ti-Doped Ta3N5 Thin Films for Enhanced Photoelectrochemical Water Splitting: Electronic Structure Modulation and Charge Carrier Dynamics Small Structures, Article e202500504 (Article in journal) Continue to DOI

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