Dresden 2026 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 57: Nitrides IV – Optical properties

HL 57.2: Talk

Friday, March 13, 2026, 11:45–12:00, POT/0051

Optical properties of ScAlN: investigation by spectroscopic ellipsometry — •Christina Harms¹, Jona Grümbel¹, Duc V. Dinh², Zhuohui Chen³, Oliver Brandt², Martin Feneberg¹, and Rüdiger Goldhahn¹ — ¹Otto-von-Guericke-Universität, Institut für Physik, Magdeburg, Germany — ²Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Berlin, Germany — ³Huawei Technologies Canada Co., Ltd., Kanata, Canada

Sc_xAl_1−xN alloys are of increasing interest due to their unique ferroelectric and optoelectronic properties. In this work, we investigate the dielectric function of this material using spectroscopic ellipsometry. A series of Sc_xAl_1−xN samples with 0 ≤ x ≤ 0.35, grown on AlN/Si by plasma-assisted molecular beam epitaxy, were measured in the infrared (IR) and ultraviolet (UV) spectral range. In the IR range, the E₁(TO) phonon mode is characterized in terms of its resonance frequency ω and broadening γ, which are analyzed as a function of Sc content. Additionally, the dielectric limit ε_∞ is derived. With increasing Sc content, ω decreases, while both γ and ε_∞ increase. In the UV range, we determine the optical bandgap E_g as well as the corresponding ε_∞ and describe the observed trends across the composition range. Here, E_g decreases systematically with increasing Sc content and ε_∞ increases accordingly. The results are compared with recent results from literature, showing consistent trends in the optical properties throughout the investigated composition range.