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arXiv · 2512.01472

Optical refractive index measurements of AlGaAs at high temperature for fully automated molecular beam epitaxy growth of Bragg mirrors

Pierre Gadras·Léo Bourdon·Antoine Fées·Karim Ben Saddik·Guilhem Almuneau·Alexandre Arnoult
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Abstract

In-situ measurement is a key feature to better understand and precisely control the growth of complex structures, such as vertical-cavity surface-emitting lasers. In this work, we are showing the precise measurement of optical indices of AlGaAs at 600 {\textdegree}C over a wide spectral range (450--1400 nm). To do so, in-situ spectral reflectance measurement is used, combined with ex-situ layer thickness and composition measurement by x-ray diffraction enabling for precise determination of the optical indices with an accuracy better than 1%. To validate our measurements, we realized the complete automation of the growth of a GaAs/AlAs 940 nm-DBR by molecular beam epitaxy, without the need to pre-calibrate cells fluxes. The fabricated DBR shows a deviation of 0.2 nm of the stop-band central-wavelength compared to the targeted one. This approach holds significant interest for the III--V semiconductor community and epitaxial growth techniques.

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Pierre Gadras, Léo Bourdon, Antoine Fées, Karim Ben Saddik, Guilhem Almuneau, Alexandre Arnoult. 2025-12-01. Optical refractive index measurements of AlGaAs at high temperature for fully automated molecular beam epitaxy growth of Bragg mirrors. https://arxiv.org/abs/2512.01472

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