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oai:docta.ucm.es:20.500.14352/1250342025-10-16T23:49:11Zcom_20.500.14352_14col_20.500.14352_15

Pérez Peinado, Paula Dolado, J. Alcázar Ruano, Pedro Luis Carrasco Madrigal, Daniel Martínez Casado, María Ruth Bonino, Valentina Martínez Criado, Gema Jesenovec, Jani McCloy, John S. Domínguez-Adame Acosta, Francisco Quereda, Jorge Nogales Díaz, Emilio Méndez Martín, María Bianchi 2025-10-16T18:15:32Z 2025-10-16T18:15:32Z 2025 Pérez-Peinado, P., Dolado, J., Alcázar Ruano, P.L., Carrasco, D., Martínez-Casado, R., Bonino, V., Martínez-Criado, G., Jesenovec, J., McCloy, J.S., Domínguez-Adame, F., Quereda, J., Nogales, E. and Méndez, B. (2025), Proving Optical Anisotropy and Polarization Effects in β-Ga2O3 Nanomembranes via X-Ray Excited Optical Luminescence. Adv. Photonics Res., 6: 2500043. https://doi.org/10.1002/adpr.202500043 2699-9293 10.1002/adpr.202500043 https://hdl.handle.net/20.500.14352/125034 https://doi.org/10.1002/adpr.202500043 https://advanced.onlinelibrary.wiley.com/doi/10.1002/adpr.202500043 Monoclinic beta-Ga2O3 is a key representative material of the ultrawide-bandgap semiconductor family. The distinct atomic arrangement in beta-Ga2O3 introduces two coordination environments for Ga ions, resulting in pronounced anisotropy in its optical, electronic, and thermal properties. In this study, a synchrotron nanoprobe to investigate the anisotropic optical properties of well-oriented (100) beta-Ga2O3 nanomembranes with a thickness of 200 nm, produced through mechanical exfoliation, is employed. Polarization-resolved X-ray excited optical luminescence (XEOL) measurements reveal a strong ultraviolet (UV) emission band at 3.4 eV, which is strongly polarized along the c-axis. Additionally, XEOL data show blue (2.9 eV) and deep-UV (3.8 eV) emissions. Notably, the deep-UV band, rarely reported in conventional photoluminescence studies, is attributed to the presence of Ga vacancies, as supported by first-principles calculations. Polarization-dependent X-ray absorption near-edge structure (XANES) spectroscopy allows one to probe the distinct symmetries of the b and c crystallographic planes. Furthermore, by combining XANES and XEOL, this study investigates the site-specific contributions of Ga ions to the luminescence process. These findings highlight the potential of beta-Ga2O3 nanomembranes as a robust material platform for developing polarization-sensitive devices. The pronounced anisotropy of beta-Ga2O3 causes orientation-dependent optoelectronic properties, making it a highly promising candidate for a wide range of advanced applications eng http://creativecommons.org/licenses/by/4.0/ open access Attribution 4.0 International Proving optical anisotropy and polarization effects in β-Ga2O3 nanomembranes via X-Ray excited optical luminescence journal article