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HL: Fachverband Halbleiterphysik

HL 5: Optical Properties I

HL 5.5: Vortrag

Montag, 18. März 2024, 10:45–11:00, EW 561

Cr-doped Ga₂O₃ microcavities for thermometric applications — •Ruben Johannes Theodorus Neelissen¹, Manuel Alonso-Orts¹, Daniel Carrasco², Marco Schowalter¹, Andreas Rosenauer¹, Emilio Nogales², Bianchi Mendez², and Martin Eickhoff¹ — ¹Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany. — ²Departamento de Fisica de Materiales, Plaza Ciencias 1, Universidad Complutense de Madrid, 28040 Madrid, Spain.

Monoclinic gallium oxide (β-Ga₂O₃) is a transparent conductive oxide with an ultra-wide bandgap of 4.8 eV and high chemical and thermal resilience. This makes β-Ga₂O₃ very interesting for areas such as high power (opto)electronics.

Previous work [1] focused on chromium doped β-Ga₂O₃ microwires as optical microcavities and their use of thermometric application. Focused ion beam (FIB) fabricated distributed Bragg reflectors (DBRs) enhance the confined light in the microcavities, resulting in strong resonances. With increasing temperature, the resonant wavelength of these peaks redshifts due to changes in both the refractive index and the optical length of the cavities. The operation of these wide dynamic range thermometers with a resolution of 1 K was demonstrated [1].

However, the FIB-fabricated microcavities involve a complex fabrication process, are mechanically unstable and are not resilient to high laser powers. In this work, a new fabrication method involving atomic layer deposition (ALD) was developed.

[1] M. Alonso-Orts et al. In: Small 18.1 (2022), p. 2105355.