Strain and Band-Gap Engineering in Ge-Sn Alloys via P Doping
| Autor: | Prucnal, Slawomir, Berencén, Yonder, Wang, Mao, Grenzer, Jörg, Voelskow, Matthias, Hübner, Rene, Yamamoto, Yuji, Scheit, Alexander, Bärwolf, Florian, Zviagin, Vitaly, Schmidt-Grund, Rüdiger, Grundmann, Marius, Żuk, Jerzy, Turek, Marcin, Droździel, Andrzej, Pyszniak, Krzysztof, Kudrawiec, Robert, Polak, Maciej P., Rebohle, Lars, Skorupa, Wolfgang, Helm, Manfred, Zhou, Shengqiang |
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| Rok vydání: | 2019 |
| Předmět: | |
| Zdroj: | Phys. Rev. Applied 10, 064055 (2018) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevApplied.10.064055 |
| Popis: | Ge with a quasi-direct band gap can be realized by strain engineering, alloying with Sn, or ultrahigh n-type doping. In this work, we use all three approaches together to fabricate direct-band-gap Ge-Sn alloys. The heavily doped n-type Ge-Sn is realized with CMOS-compatible nonequilibrium material processing. P is used to form highly doped n-type Ge-Sn layers and to modify the lattice parameter of P-doped Ge-Sn alloys. The strain engineering in heavily-P-doped Ge-Sn films is confirmed by x-ray diffraction and micro Raman spectroscopy. The change of the band gap in P-doped Ge-Sn alloy as a function of P concentration is theoretically predicted by density functional theory and experimentally verified by near-infrared spectroscopic ellipsometry. According to the shift of the absorption edge, it is shown that for an electron concentration greater than 1x10^20 cm-3 the band-gap renormalization is partially compensated by the Burstein-Moss effect. These results indicate that Ge-based materials have high potential for use in near-infrared optoelectronic devices, fully compatible with CMOS technology. Comment: 20 pages, 6 figures |
| Databáze: | arXiv |
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