Direct bandgap quantum wells in hexagonal Silicon Germanium

• Published in: Nature communications Vol. 15; no. 1; pp. 5252 - 11
• Main Authors: Peeters, Wouter H. J., van Lange, Victor T., Belabbes, Abderrezak, van Hemert, Max C., Jansen, Marvin Marco, Farina, Riccardo, van Tilburg, Marvin A. J., Verheijen, Marcel A., Botti, Silvana, Bechstedt, Friedhelm, Haverkort, Jos. E. M., Bakkers, Erik P. A. M.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 19.06.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/1019/1020/1093; 639/301/1019/482; 639/624/399/1099; 639/925/357/1016; Alignment; Crystal structure; Germanium; Heterostructures; Humanities and Social Sciences; Light emission; Light sources; Luminescence; Microscopy; multidisciplinary; Optoelectronic devices; Photoluminescence; Photonic band gaps; Photons; Quantum confinement; Quantum dots; Quantum wells; Room temperature; Science; Science (multidisciplinary); Semiconductors; Silicon; Silicon germanides; Synthesis; Wells
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-49399-3

Silicon is indisputably the most advanced material for scalable electronics, but it is a poor choice as a light source for photonic applications, due to its indirect band gap. The recently developed hexagonal Si 1− x Ge x semiconductor features a direct bandgap at least for x  > 0.65, and the realization of quantum heterostructures would unlock new opportunities for advanced optoelectronic devices based on the SiGe system. Here, we demonstrate the synthesis and characterization of direct bandgap quantum wells realized in the hexagonal Si 1− x Ge x system. Photoluminescence experiments on hex-Ge/Si 0.2 Ge 0.8 quantum wells demonstrate quantum confinement in the hex-Ge segment with type-I band alignment, showing light emission up to room temperature. Moreover, the tuning range of the quantum well emission energy can be extended using hexagonal Si 1− x Ge x /Si 1− y Ge y quantum wells with additional Si in the well. These experimental findings are supported with ab initio bandstructure calculations. A direct bandgap with type-I band alignment is pivotal for the development of novel low-dimensional light emitting devices based on hexagonal Si 1− x Ge x alloys, which have been out of reach for this material system until now. Authors demonstrate the synthesis and characterization of direct bandgap quantum wells in the hexagonal Si 1− x Ge x system. Photoluminescence experiments show light emission up to room temperature, and the emission wavelength can be tuned by thickness of the wells and the Si composition.