SPIN 1 CENTERS IN NEUTRON IRRADIATED SILICON
Abstract
Electron paramagnetic resonance of radiation induced defects in neutron irradiated silicon crystals has been studied. Measurements were made as a function of annealing on samples which attained intrinsic resistivity after fast neutron bombardment in a reactor. The measurements were made at temperatures of 300°K, 77%, and 4.2 K, with superheterodyne spectrometers operating at 24 kmc/s and 9.4 km/s.Through analysis of the anisotropy of the resonance spectra, isochronal annealing experiments, and field dependence of the spectra at 24 kme/s and at 9.4 kme/s, four spin 1 centers were isolated. The g-tensors and the magnitude of the zero field splitting terms are compatible with systems having a pair of elec- trons primarily localized in two (111) dangling bond orbitals separated from each other along a (110) direction by a distance of the order of a lattice spacing. The observed resonance arises from the triplet levels produced by a vesk exchange interaction. From the low temperature measurements, an upper limit of the triplet-singlet separation is estimated to be 50 ca.
Degree
Ph.D.
Subject Area
Condensed matter physics
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