1. A demonstration of donor passivation through direct formation of V-Asi complexes in As-doped Ge1−xSnx.
- Author
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Khanam, Afrina, Vohra, Anurag, Slotte, Jonatan, Makkonen, Ilja, Loo, Roger, Pourtois, Geoffrey, and Vandervorst, Wilfried
- Subjects
CHEMICAL vapor deposition ,EPITAXIAL layers ,PASSIVATION ,POSITRON annihilation ,POSITRONS - Abstract
Positron annihilation spectroscopy in the Doppler and coincidence Doppler mode was applied on Ge 1 − x Sn x epitaxial layers, grown by chemical vapor deposition with different total As concentrations (∼ 10 19 – 10 21 cm − 3 ), high active As concentrations (∼ 10 19 cm − 3 ), and similar Sn concentrations (5.9%–6.4%). Positron traps are identified as mono-vacancy complexes. Vacancy-As complexes, V-As i , formed during the growth were studied to deepen the understanding of the electrical passivation of the Ge 1 − x Sn x :As epilayers. Larger mono-vacancy complexes, V-As i (i ≥ 2), are formed as the As doping increases. The total As concentration shows a significant impact on the saturation of the number of As atoms (i = 4) around the vacancies in the sample epilayers. The presence of V-As i complexes decreases the dopant activation in the Ge 1 − x Sn x :As epilayers. Furthermore, the presence of Sn failed to hinder the formation of larger V-As i complexes and thus failed to reduce the donor-deactivation. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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