Transport and electrically detected electron spin resonance of microcrystalline silicon before and after electron irradiation

ABSTRACTThe effect of micro-doping, defect creation, and non-steady state occupation through optical transitions on the electron spin resonance signals found in undoped and weakly doped microcrystalline silicon with a high degree of crystallinity is investigated. The experimental results are in agreement with the assignment of the resonance at g=1.9983 to conduction electrons in the crystalline grains and the resonanccs around g=2.0052 to dangling bonds in the remaining amorphous phase and at the grain boundaries. The simultaneous presence of both resonances can result from a large conduction band offset between crystalline grains and grain boundaries or the amorphous phase. The presence of conduction electron spin resonance in compensated and even p-type material points also to potential fluctuations. Free electrons in interconnected crystalline grains are in agreement with the weakly activated transport found in µc-Si:H at low temperatures.

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Defect and Tail States in Microcrystalline Silicon investigated by pulsed ESR

MRS Proceedings ◽

10.1557/proc-609-a27.3 ◽

2000 ◽

Vol 609 ◽

Cited By ~ 23

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.

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Electron spin resonance and CNDO/2 study of the radicals produced during fast electron irradiation of substances containing nitrogen. Part 3.—Piperidine

Journal of the Chemical Society Faraday Transactions 2 Molecular and Chemical Physics ◽

10.1039/f29747001912 ◽

1974 ◽

Vol 70 (0) ◽

pp. 1912-1919 ◽

Cited By ~ 5

Author(s):

George A. Helcké ◽

Roberto Fantechi

Keyword(s):

Electron Spin Resonance ◽

Electron Spin ◽

Electron Irradiation ◽

Fast Electron ◽

Spin Resonance

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ChemInform Abstract: ELECTRON SPIN RESONANCE AND CNDO/2 STUDY OF THE RADICALS PRODUCED DURING FAST ELECTRON IRRADIATION OF SUBSTANCES CONTAINING NITROGEN PART 3, PIPERIDINE

Chemischer Informationsdienst ◽

10.1002/chin.197503065 ◽

1975 ◽

Vol 6 (3) ◽

Author(s):

GEORGE HELCKE ◽

ROBERTO FANTECHI

Keyword(s):

Electron Spin Resonance ◽

Electron Spin ◽

Electron Irradiation ◽

Fast Electron ◽

Spin Resonance

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Photocarrier Recombination in Microcrystalline Silicon Studied by Light Induced Electron Spin Resonance Transients

MRS Proceedings ◽

10.1557/proc-452-827 ◽

1996 ◽

Vol 452 ◽

Cited By ~ 4

Author(s):

J. Müller ◽

F. Finger ◽

C. Malten ◽

H. Wagner

Keyword(s):

Electron Spin Resonance ◽

Electron Spin ◽

Doping Level ◽

Infrared Light ◽

Microcrystalline Silicon ◽

Excitation Energies ◽

Time Resolved ◽

Dark Light ◽

Spin Resonance ◽

Initial Excitation

AbstractTo get information on the density of states distribution and the photocarrier recombination in microcrystalline silicon (μc-Si:H), samples with various amounts of n- and p-type doping are studied with electron spin resonance (ESR) and stationary and time-resolved light induced ESR. The intensity of the dark ESR signals from dangling bonds (DB) and conduction electrons (CESR) is investigated as a function of the doping level. The DB signal has a flat distribution over a wide doping range while the CESR signal strongly increases with n-type doping. Upon illumination with white or infrared light both resonances are enhanced with an intensity that depends on the doping level. The decay of the light induced signal and the dependence in time and intensity of the residual signal on different initial excitation energies and dark/light -sequences is studied. The results are discussed with a schematic band diagram for μc-Si:H. The existence of a potential barrier is proposed which spatially separates photogenerated carriers. A large band-offset between crystalline and disordered regions is further suggested.

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