Direct bandgap group IV materials could provide intimate integration of lasers, amplifiers, and compact modulators within complementary metal–oxide–semiconductor for smaller, active silicon photonics. Dilute germanium carbides (GeC) with ∼1 at. % C offer a direct bandgap and strong optical emission, but energetic carbon sources such as plasmas and e-beam evaporation produce defective materials. In this work, we used CBr4 as a low-damage source of carbon in molecular beam epitaxy of tin-free GeC, with smooth surfaces and narrow x-ray diffraction peaks. Raman spectroscopy showed substitutional incorporation of C and no detectable sp2 bonding from amorphous or graphitic carbon, even without surfactants. Photoluminescence shows strong emission compared with Ge.
This content will become publicly available on August 21, 2025
- Award ID(s):
- 2204202
- PAR ID:
- 10552095
- Publisher / Repository:
- ACS
- Date Published:
- Journal Name:
- Journal of the American Chemical Society
- Volume:
- 146
- Issue:
- 33
- ISSN:
- 0002-7863
- Page Range / eLocation ID:
- 23582 to 23590
- Subject(s) / Keyword(s):
- carbon nanotubes, cyclization, functionalization, quantum defects, organic color centers
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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