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Sn Vacancies In Photorefractive Sn2P2S6 Crystals: An Electron Paramagnetic Resonance Study Of An Optically Active Hole Trap, Eric M. Golden, Sergey A. Basun, D. R. Evans, A. A. Grabar, I. M. Stoika, Nancy C. Giles, Larry E. Halliburton
Sn Vacancies In Photorefractive Sn2P2S6 Crystals: An Electron Paramagnetic Resonance Study Of An Optically Active Hole Trap, Eric M. Golden, Sergey A. Basun, D. R. Evans, A. A. Grabar, I. M. Stoika, Nancy C. Giles, Larry E. Halliburton
Faculty Publications
Electron paramagnetic resonance (EPR) is used to identify the singly ionized charge state of the Sn vacancy (V−Sn) in single crystals of Sn2P2S6 (often referred to as SPS). These vacancies, acting as a hole trap, are expected to be important participants in the photorefractive effect observed in undoped SPS crystals. In as-grown crystals, the Sn vacancies are doubly ionized (V2−Sn) with no unpaired spins. They are then converted to a stable EPR-active state when an electron is removed (i.e., a hole is trapped) during an illumination below 100 K …
Oxygen Vacancies In Lialo2 Crystals, Maurio S. Holston, I. P. Ferguson, John W. Mcclory, Nancy C. Giles, Larry E. Halliburton
Oxygen Vacancies In Lialo2 Crystals, Maurio S. Holston, I. P. Ferguson, John W. Mcclory, Nancy C. Giles, Larry E. Halliburton
Faculty Publications
Singly ionized oxygen vacancies are produced in LiAlO2 crystals by direct displacement events during a neutron irradiation. These vacancies, with one trapped electron, are referred to as V+O centers. They are identified and characterized using electron paramagnetic resonance (EPR) and optical absorption. The EPR spectrum from the V+O centers is best monitored near 100 K with low microwave power. When the magnetic field is along the [001] direction, this spectrum has a g value of 2.0030 and well-resolved hyperfine interactions of 310 and 240 MHz with the two 27Al nuclei that are adjacent to the oxygen vacancy. A second …
Sulfur Vacancies In Photorefractive Sn2P2S6 Crystals, Eric M. Golden, Sergey A. Basun, A. A. Grabar, I. M. Stoika, Nancy C. Giles, D. R. Evans, Larry E. Halliburton
Sulfur Vacancies In Photorefractive Sn2P2S6 Crystals, Eric M. Golden, Sergey A. Basun, A. A. Grabar, I. M. Stoika, Nancy C. Giles, D. R. Evans, Larry E. Halliburton
Faculty Publications
A photoinduced electron paramagnetic resonance (EPR) spectrum in single crystals of Sn2P2S6 (SPS) is assigned to an electron trapped at a sulfur vacancy. These vacancies are unintentionally present in undoped SPS crystals and are expected to play an important role in the photorefractive behavior of the material. Nonparamagnetic sulfur vacancies are formed during the initial growth of the crystal. Subsequent illumination below 100 K with 442 nm laser light easily converts these vacancies to EPR-active defects. The resulting S = 1/2 spectrum shows well-resolved and nearly isotropic hyperfine interactions with two P ions and two Sn ions. Partially resolved interactions …