High Frequency Electron Spin Resonance Study of Hydrogenated Microcrystalline Silicon

2003 ◽  
Vol 762 ◽  
Author(s):  
Takashi Ehara
Keyword(s):  
Electron Spin Resonance ◽  
Substrate Temperature ◽  
Electron Spin ◽  
Esr Spectra ◽  
Electron Spin Resonance Study ◽  
Dangling Bond ◽  
Microcrystalline Silicon ◽  
W Band ◽  
X Band ◽  
Spin Resonance

AbstractDangling bond defects (DB) in hydrogenated microcrystalline silicon (μc-Si:H) have been studied by X-band (9 GHz) Q-band (33 GHz) and W-band (90 GHz) electron spin resonance (ESR) spectroscopy. In X-band ESR spectra, all the samples showed asymmetric dangling bond defect signal at g = 2.005 – 2.006. The DB signal shape shows little dependence on substrate temperature in the X-band electron spin resonance (ESR) spectra. In the Q-band and W-band ESR spectra, existence of two centers in DB signals is clearly indicated by the shape of the spectra. The Q-band ESR spectra shape reviles that the peak of one center is at g = 2.0055andthe other is around at g = 2.0060. In addition, the DB signal showed dependence on substrate temperature. The dependence of the DB signals can be explained by difference of intensity ratio of the peaks by these two centers. The signal at g = 2.0060 is consistent with the asymmetric ESR signal observed in the microcrystalline silicon embedded in SiO2. W-band ESR measurement indicates that the signal observed at g = 2.0060 is due to single inhomogeneous species and does not consist of plural species.

Defect and Tail States in Microcrystalline Silicon investigated by pulsed ESR

2000 ◽  
Vol 609 ◽  
Author(s):  
P. Kanschat ◽  
H. Mell ◽  
K. Lips ◽  
W. Fuhs
Keyword(s):  
Electron Spin Resonance ◽  
Detailed Analysis ◽  
Electron Spin ◽  
Qualitative Model ◽  
Dangling Bond ◽  
Microcrystalline Silicon ◽  
Band Tail ◽  
Spin Resonance ◽  
Donor States ◽  
Broad Structure

ABSTRACTWe report on a detailed analysis of paramagnetic states in a doping series of microcrystalline silicon, μc-Si:H, by pulsed electron spin resonance. We identify two dangling bond like structures at g = 2.0052 (db1) and g = 2.0043 (db2). Whereas db1 is evenly distributed in the gap, the db2 state is found to be localized in the lower part of the gap. The CE resonance at g ≈ 1.998 is assigned to electrons in conduction band tail states. In p-doped samples, we observe a broad structure CH at g ≈ 2.08 which we identify with holes trapped in valence band tail states. It is shown that the CH state behaves very similar on illumination as the CE resonance. In n-type samples a pair of hyperfine split lines (A ≈ 11 mT) is found which apparently does not originate from 31P-donor states. On the basis of our results we propose a qualitative model for paramagnetic states in μc-Si:H.

Electron Spin Resonance Study of the Dangling Bond in a-Si:H and Porous Silicon

1993 ◽  
Vol 297 ◽  
Author(s):  
T.J. Mc Mahon ◽  
Y. Xiao
Keyword(s):  
Electron Spin Resonance ◽  
Porous Silicon ◽  
Electron Spin ◽  
Electrochemical Etching ◽  
Bond Line ◽  
Electron Spin Resonance Study ◽  
Dangling Bond ◽  
Porous Si ◽  
Spin Resonance ◽  
G Value

We compare the electron spin resonance (ESR) signal of the dangling bond in porous silicon films, produced by electrochemical etching, to the ESR signal from hydrogenated amorphous Si (a-Si:H). The anisotropy of the ESR signal in porous Si showed g values varying as for the Pb Si/SiO2 interface dangling bond. The g value varies from g|| − 2.0020 to gL − 2.0080 with an inhomogeneously broadened line width increasing from 1.8 to 3.8 G. A porous Si ESR powder line, with superhyperfine and strain broadening intrinsic to porous Si, is compared to the a−Si:H dangling bond line. The result is more inhomogeneous broadening of line widths parallel and perpendicular to the dangling bond axis in a-Si:H, and less anisotropy in g|| − gL- No evidence was seen for light-induced metastability on a H-passivated porous Si film.

Mass spectrometric and electron spin resonance study of allylic peroxyl radicals in the gas-phase reaction between allylic radicals and dioxygen

1986 ◽  
Vol 51 (12) ◽  
pp. 2675-2684 ◽  
Author(s):  
Karel Mach ◽  
Jana Nováková ◽  
Vladimír Hanuš ◽  
Zdeněk Dolejšek
Keyword(s):  
Electron Spin Resonance ◽  
Gas Phase ◽  
Electron Spin ◽  
Esr Spectra ◽  
Mass Spectrometric ◽  
Peroxyl Radicals ◽  
Electron Spin Resonance Study ◽  
Phase Reaction ◽  
Mass Spectrometric Measurement ◽  
Spin Resonance

Mass spectrometric measurement of the pyrolyzed (790-1 030 K) mixture of 1,5-hexadiene or 2,5-dimethyl-1,5-hexadiene with dioxygen afforded no evidence for the presence of allylic peroxyl radicals or aldehydes in the gas phase though the allylic radicals were readily detected at low ionization potentials. On the other side, the electron spin resonance measurement revealed that the allylic radicals were converted quantitatively to allylic peroxyl radicals during condensation of pyrolytic mixtures at 77 K, and acrolein and methacrolein were found mass spectrometrically after thawing of the condensed pyrolytic material as stable products of the allylperoxyl and 2-methylallylperoxyl radical, respectively. These results are compatible with the temperature dependent dissociation equilibrium of the allylic peroxyl radicals. The allylic peroxyl radicals were trapped at 77 K using co-condensation with adamantane from the gas phase in yields as high as 30-50% of the radicals produced in pyrolysis. The electron spin resonance spectra showed partial motional freedom of the peroxyl radicals when they were trapped in the low-contaminated adamantane matrix at 77 K, but in matrices highly contaminated with the biallyl hydrocarbon and products of pyrolysis the ESR spectra indicated rigidly trapped peroxyl radicals. Free rotation of the allylic peroxyl radicals in both types of matrices occurred at 110 K.

Computer Simulation of Electron Spin Resonance Spectra of Ge25S75and Ge30S70 Bulk Glasses

1997 ◽  
Vol 62 (11) ◽  
pp. 1721-1729
Author(s):  
Zdeněk Černošek ◽  
Marek Liška ◽  
Peter Pelikán ◽  
Eva Černošková ◽  
Marián Valko ◽  
...  
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Liquid Nitrogen Temperature ◽  
Esr Spectra ◽  
Dangling Bond ◽  
Paramagnetic Defect ◽  
Bond Model ◽  
Spin Resonance ◽  
Bulk Glasses ◽  
Good Agreement

The electron spin resonance (ESR) spectra of bulk glasses of the chemical composition Ge25S75 and Ge30S70 were measured at liquid nitrogen temperature and subjected to computerized separation. The complex ESR spectra of both glasses were found to represent a superposition of three paramagnetic defect spectra, two with orthorhombic tensors g and one with the axial tensor g. The former two paramagnetic centers can be related to a two-atomic defect of the sulfur-sulfur type, the latter to a germanium-sulfur defect. The experimental results are in a good agreement with the non-dangling bond model of paramagnetic defects in Ge-S glasses.

Structure of radicals produced by γ-radiolysis. Part 4. Adamantane matrices doped with various 5-membered heterocyclic molecules

1976 ◽  
Vol 54 (12) ◽  
pp. 1971-1984 ◽  
Author(s):  
D. L. Winters ◽  
A. Campbell Ling
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Room Temperature ◽  
Esr Spectra ◽  
Heterocyclic Molecules ◽  
First Derivative ◽  
X Band ◽  
Spin Resonance ◽  
Spin Center ◽  
Esr Spectrometry

The effects of γ-adiolysis at room temperature on adamantane and adamantane-d16 matrices doped with 5-membered heterocyclic molecules has been examined by X-band electron spin resonance (esr) spectrometry. Radical structures formed from heterocyclic solute molecules are discussed and tentative assignments made for 2-methyl-, 3-methyl-, and 2,5-dimethylthiophene, 2-methyl-, and 2,5-dimethylfuran. Discussion of possible radical structures derived from furan, tetrahydrofuran, 2-methyl- and 3-methyltetrahydrofuran, 2,5-dihydrofuran, and 4,5-dihydro-2-methylfuran, is included, but unambiguous assignments of structure cannot be made for these compounds from the esr data obtained. Other molecules examined included thiophene, pyrrole, and 1-methyl- and 1,2,5-trimethylpyrrole. For these latter molecules, experimentally obtained first derivative X-band esr spectra were too poorly resolved to allow rational discussion of possible structures. It was noted that perdeuterated adamantane matrices provided superior resolution for esr spectra derived from radicals with a delocalized spin center such as allyl or allenyl species.

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