Regensburg 2022 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 37: Thermal Properties
HL 37.1: Vortrag
Donnerstag, 8. September 2022, 16:30–16:45, H34
Thermal characterization of semiconductor membranes by Raman thermometry — •Isabell Hüllen1, Mahmoud Elhajhasan1, Wilken Seemann1, Markus R. Wagner2, and Gordon J. Callsen1 — 1Institut für Festkörperphysik, Universität Bremen, Germany — 2Institut für Festkörperphysik, Technische Universität Berlin, Germany
Photonic structures like nanolasers are often based on freestanding semiconductor membranes comprising hole lattices. As a result, a high number of interfaces limits the thermal conductivity and consequently the overall device performance under high injection conditions. Thus, it remains an open task to correlate the thermal and optical characterization of photonic membranes often based on III-V semiconductors. In this contribution we follow a careful step-by-step approach to attest the suitability of Raman thermometry (RT) for a precise determination of the thermal conductivity κ. First, we analyse a well-studied bulk material like Ge to not only extract κ, but also to assess underlying errors and experimental limitations. Consequently, the RT technique is applied to Ge membranes, in preparation of the subsequent thermal characterization of photonic membranes. Here, we characterize a 250-nm-thick c-plane GaN membrane, which forms the basis for state-of-the-art nanobeam lasers. RT reveals that κ is reduced by up to one order of magnitude in comparison to bulk values. The pronounced Photoluminescence signal of our GaN membrane directly enables an alternative optical and thermal characterization, which we link to RT, aiming to bridge optical and thermal material characterization.