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Charge transition level of GePb1 centers at interfaces of SiO2/Ge xSi1− x/SiO2 heterostructures investigated by positron annihilation spectroscopy.
- Source :
- Physica Status Solidi (B); Nov2014, Vol. 251 Issue 11, p2211-2215, 5p
- Publication Year :
- 2014
-
Abstract
- In this work, we address the charge trapping properties of Ge dangling bond (DB) defects - GeP<subscript>b1</subscript> centers as typified by electron spin resonance spectroscopy (ESR) - found at the interfaces between condensation-grown Si<subscript>1− x</subscript>Ge<subscript> x</subscript> (0.28 < x < 0.8) alloys and insulating SiO<subscript>2</subscript>. The ESR observation of singly-occupied paramagnetic GeP<subscript>b1</subscript> centers, carried out at 4.3 K, is complemented by temperature-dependent positron annihilation spectroscopy (PAS) in the Doppler broadening mode, which enables observation of the neutral-to-negative defect transitions as the temperature increases from 50 to 300 K. Through correlation of this re-charging behavior with the temperature-induced shift of the Fermi energy, the energy of the Ge DB −/0 transition in the Si<subscript>0.27</subscript>Ge<subscript>0.73</subscript> alloy is inferred to be energetically distributed in a ∼0.1 eV interval above the top of the semiconductor valence band. This result refines previous estimates from capacitance-voltage measurements, thus providing independent affirmation that the energy levels of Ge DBs lie inside the band gap of the Si<subscript>1− x</subscript>Ge<subscript> x</subscript> alloys. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 03701972
- Volume :
- 251
- Issue :
- 11
- Database :
- Complementary Index
- Journal :
- Physica Status Solidi (B)
- Publication Type :
- Academic Journal
- Accession number :
- 99086985
- Full Text :
- https://doi.org/10.1002/pssb.201400040