From pseudo-direct hexagonal germanium to direct silicon-germanium alloys
Borlido P, Suckert JR, Furthmueller J, Bechstedt F, Botti S, Roedl C (2021)
Publication Type: Journal article
Publication year: 2021
Journal
Book Volume: 5
Article Number: 114604
Journal Issue: 11
DOI: 10.1103/PhysRevMaterials.5.114604
Abstract
We present ab initio calculations of the electronic and optical properties of hexagonal SixGe1-x alloys in the lonsdaleite structure. Lattice constants and electronic band structures in excellent agreement with experiment are obtained using density-functional theory. Hexagonal Si has an indirect band gap, whereas hexagonal Ge has a pseudo-direct gap, i.e., the optical transitions at the minimum direct band gap are very weak. The pseudo-direct character of pure hexagonal Ge is efficiently lifted by alloying. Already for a small admixture of Si, symmetry reduction enhances the oscillator strength of the lowest direct optical transitions. The band gap is direct for a Si content below 45 %. We validate lonsdaleite group-IV alloys to be efficient optical emitters, suitable for integrated optoelectronic applications.
Involved external institutions
Germany (DE)How to cite
APA:
Borlido, P., Suckert, J.R., Furthmueller, J., Bechstedt, F., Botti, S., & Roedl, C. (2021). From pseudo-direct hexagonal germanium to direct silicon-germanium alloys. Physical Review Materials, 5(11). https://doi.org/10.1103/PhysRevMaterials.5.114604
MLA:
Borlido, Pedro, et al. "From pseudo-direct hexagonal germanium to direct silicon-germanium alloys." Physical Review Materials 5.11 (2021).
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