TY - JOUR

T1 - Combined multifrequency EPR and DFT study of dangling bonds in a-Si

T2 - H

AU - Fehr, Matthias

AU - Schnegg, A.

AU - Rech, B.

AU - Lips, K.

AU - Astakhov, Oleksandr

AU - Finger, Friedhelm

AU - Pfanner, G.

AU - Freysoldt, C.

AU - Neugebauer, J.

AU - Bittl, Robert

AU - Teutloff, Christian

PY - 2011/12/13

Y1 - 2011/12/13

N2 - Multifrequency pulsed electron paramagnetic resonance (EPR) spectroscopy using S-, X-, Q-, and W-band frequencies (3.6, 9.7, 34, and 94 GHz, respectively) was employed to study paramagnetic coordination defects in undoped hydrogenated amorphous silicon (a-Si:H). The improved spectral resolution at high magnetic field reveals a rhombic splitting of the g tensor with the following principal values: g x=2.0079, g y=2.0061, and g z=2.0034, and shows pronounced g strain, i.e., the principal values are widely distributed. The multifrequency approach furthermore yields precise 29Si hyperfine data. Density functional theory (DFT) calculations on 26 computer-generated a-Si:H dangling-bond models yielded g values close to the experimental data but deviating hyperfine interaction values. We show that paramagnetic coordination defects in a-Si:H are more delocalized than computer-generated dangling-bond defects and discuss models to explain this discrepancy.

AB - Multifrequency pulsed electron paramagnetic resonance (EPR) spectroscopy using S-, X-, Q-, and W-band frequencies (3.6, 9.7, 34, and 94 GHz, respectively) was employed to study paramagnetic coordination defects in undoped hydrogenated amorphous silicon (a-Si:H). The improved spectral resolution at high magnetic field reveals a rhombic splitting of the g tensor with the following principal values: g x=2.0079, g y=2.0061, and g z=2.0034, and shows pronounced g strain, i.e., the principal values are widely distributed. The multifrequency approach furthermore yields precise 29Si hyperfine data. Density functional theory (DFT) calculations on 26 computer-generated a-Si:H dangling-bond models yielded g values close to the experimental data but deviating hyperfine interaction values. We show that paramagnetic coordination defects in a-Si:H are more delocalized than computer-generated dangling-bond defects and discuss models to explain this discrepancy.

UR - http://www.scopus.com/inward/record.url?scp=84855459784&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.84.245203

DO - 10.1103/PhysRevB.84.245203

M3 - Article

AN - SCOPUS:84855459784

VL - 84

JO - Physical Review B

JF - Physical Review B

SN - 2469-9950

IS - 24

M1 - 245203

ER -