This title appears in the Scientific Report :
1999
Please use the identifier:
http://hdl.handle.net/2128/20228 in citations.
Electron spin resonance studies on microcrystalline silicon
Electron spin resonance studies on microcrystalline silicon
VHF-PECVD was used to prepare undoped as well as p- and n-type microcrystalline silicon with gas phase doping levels between 1 and 160 ppm and high crystalline volume fractions. The material was studied by steady state and transient electron spin resonance (ESR) at temperatures between 4 .2 and 300...
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Personal Name(s): | Müller, J. (Corresponding author) |
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Contributing Institute: |
Institut für Schicht- und Ionentechnik; ISI |
Imprint: |
Jülich
Forschungszentrum, Zentralbibliothek
1999
|
Dissertation Note: |
Aachen, Techn. Hochsch., Diss., 1999 |
Document Type: |
Book Dissertation / PhD Thesis |
Research Program: |
ohne FE |
Series Title: |
Berichte des Forschungszentrums Jülich
3615 |
Subject (ZB): | |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
VHF-PECVD was used to prepare undoped as well as p- and n-type microcrystalline silicon with gas phase doping levels between 1 and 160 ppm and high crystalline volume fractions. The material was studied by steady state and transient electron spin resonance (ESR) at temperatures between 4 .2 and 300 K in the dark and under light illumination . The results are related to transport measurements . and the nature and energy position of the respective electronic states is clarified . Two resonances of defect states a.ppear at g-values of 2 .0043 and 2 .0052 over a wide doping ra.nge pointing to either a wide distribution in energy (0 .6 eV) or considera.ble potential fluctuations . A third resonance (b value around 1 .998) is due to donor. conduction band or conduction band tail states ; the respective occupancies depending on both temperature and doping level . In particula.r, for n-type samples the spin density of this latter resonance equals the donor density over two orders of magnitude . Hyperfine interaction with phosphorus nuclei is only observed at intermediate doping levels . A value of 12 A is found for the localization length of the donor wavefunction . The conduction process at temperatures below 20 K takes place via hopping between donor or conduction band tail states with a thermal activation energy of 3 .5 meV, while at higher temperatures carriers are excited into the conduction band . Illumination with White light (energy > 1 .75 eV) at low temperatures enhances different resonances depending on type and level of doping . In contrast to amorphous silicon, infrared light with energies smaller than 0 .67 eV also lea.ds to a light-induced signal enhancement. Transient light-induced ESR data are discussed in terms of a simple model, which includes both crvsta.lline and disordered/grain boundary regions separated from each other by potential barriers |