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Energy Levels of Zn in Si 1—x Ge x Alloys: The Change‐Over from Highly Localized Deep States to Shallow‐Level Centers
Author(s) -
Voss S.,
Bracht H.,
Stolwijk N.A.,
Kringhøj P.,
Nylandsted Larsen A.
Publication year - 1998
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(199812)210:2<771::aid-pssb771>3.0.co;2-h
Subject(s) - deep level transient spectroscopy , acceptor , materials science , band gap , offset (computer science) , germanium , range (aeronautics) , spectroscopy , band offset , condensed matter physics , optoelectronics , valence band , physics , silicon , computer science , composite material , programming language , quantum mechanics
Deep level transient spectroscopy measurements were performed on Zn‐doped Si 1— x Ge x with x between 0 and 0.48. Our investigations reveal two deep hole traps which are attributed to the acceptor states Zn 0/− and Zn −/—2 of substitutional Zn. Taking into account band‐offset data for Si 1— x Ge x , we have found that the energy level related to Zn 0/− is horizontally aligned across the composition‐dependent bandgap for x up to ≈30 at% Ge which gives evidence for a localized defect state in this composition range. For higher Ge concentrations the data suggest a continuous change‐over to a shallow level center. The defect level related to the second hole trap decreases with increasing Ge content.