Microwave studies of amorphous silicon

Electron paramagnetic resonance and electron spin relaxation rates of the intrinsic paramagnetic center (g=2.0055) in amorphous silicon have been studied in the 0.3 -1.2 K temperature range. Various sample preparation techniques were used, including ion implantation, sputtering, arid vacuum evaporation. The temperature dependence of the spin lattice relaxation rates depends somewhat on sample preparation but is always very close to simple T power laws. The n values observed in this study fall into two ranges: 2.09 -2.36 and 3.26 -3.47. Comparison of measurements at 9.3 GHz and 16.5 GHz indicates that the observed rates are independent or very nearly independent of microwave frequency and applied magnetic field. Conventional one and two phonon spin lattice relaxation mechanisms cannot account for the observed temperature dependences. A theory involving spin lattice relaxation by coupling to a distribution of two level systems (TLS) is presented. The theory is adjusted so that it can be applied in the relevant temperature range and its predictions are compared to the experimental results. An attempt is made to identify the TLS and the TLS-spin coupling using electron-nuclear double rescnance (ENDOR), microwave frequency dielectric absorption, and magn

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2011

Author dc:creator

• Askew, Thomas Rendall

Contributors dc:contributor

• Stapleton, H.J.

• amorphous silicon
• electron paramagnetic resonance
• electron spin relaxation

Statement dc:rights

• 1984 Thomas Rendall Askew

Language dc:language

en

Identifier

826531

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/25309