Nature of paramagnetic centers in a-Si and a-Si:H

Journal Article · Mon Aug 01 04:00:00 EDT 1988 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.38.2779· OSTI ID:6865677

Wu, Y; Stesmans, A

A comparative ESR study has been undertaken of various kinds of a-Si and a-Si:H. Experiments on sputtered samples reveal that the local configuration of the usual dangling-bond (DB) centers (gapprox. =2.0055) depends on the details of deposition. The g value may gradually be reduced to values as low as 2.0041 as a result of local-structure change. Regarding the g = 2.004 signal originated from conduction-band-tail (CBT) states, it is shown that the effective correlation energy (U/sub eff/) is large and the temperature dependence of its spin density is due to the presence of donor levels: not due to a small-U/sub eff/ effect as has previously been concluded. Related to this, ample evidence is provided, indicating that the g = 2.004 signal in P-doped a-Si:H and the g = 2.005 DB line are in fact variants of the same kind of defect. Systematic analysis identifies the g = 2.004 CBT states signal with T/sub 3//sup -/-T/sub 3//sup +/+e/sup -/ defect centers thus showing that a great deal of the CBT states are defect states rather than disorder-induced localized states. Regarding the g = 2.013 signal in a-Si:H, evidence is provided showing that this cannot be associated with valence-band-tail states. Rather it concerns defects positioned at approx. =0.6 eV above the valence-band mobility edge, whose nature is as yet to be determined. Their presence relates directly or indirectly to H incorporation.

• Research Organization: Departement Natuurkunde, Katholieke Universiteit Leuven, B-3030 Leuven, Belgium
• OSTI ID: 6865677
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 38:4; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
COLOR CENTERS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELECTRON SPIN RESONANCE
ELECTRONIC STRUCTURE
ELEMENTS
FILMS
HYDRIDES
HYDROGEN COMPOUNDS
MAGNETIC RESONANCE
MAGNETISM
ORGANIC COMPOUNDS
ORGANIC SILICON COMPOUNDS
PARAMAGNETISM
POINT DEFECTS
RESONANCE
SEMIMETALS
SILANES
SILICON
SILICON COMPOUNDS
THIN FILMS
VACANCIES