GENERATION MECHANISM OF PHOTOINDUCED PARAMAGNETIC CENTERS FROM PREEXISTING PRECURSORS IN HIGH-PURITY SILICAS

被引:96
作者
NISHIKAWA, H
NAKAMURA, R
TOHMON, R
OHKI, Y
SAKURAI, Y
NAGASAWA, K
HAMA, Y
机构
[1] SAGAMI INST TECHNOL,DEPT ELECT ENGN,FUJISAWA,KANAGAWA 251,JAPAN
[2] WASEDA UNIV,SCI & ENGN RES LAB,SHINJUKU KU,TOKYO 169,JAPAN
来源
PHYSICAL REVIEW B | 1990年 / 41卷 / 11期
关键词
D O I
10.1103/PhysRevB.41.7828
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
High-purity silicas synthesized by various manufacturing methods were studied by electron-spin resonance after being irradiated by ArF excimer laser (6.4 eV) at room temperature. Ee centers (?Si) are induced in all samples, while nonbridging oxygen hole centers (?Si-O) appear only in oxygen-surplus silicas and in a sample which has an absorption band at 5.1 eV. The concentration of Ee centers varies from sample to sample, ranging between 1014 and 1016 spins/cm3 for the exposure at the average power density of 28 mJ/cm2 per pulse at 15 Hz for 1 h. The sample dependence regarding the species and concentrations of photoinduced defects is well explained in terms of transformation of preexisting precursors to paramagnetic defects through a two-photon-absorption process. © 1990 The American Physical Society.
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页码:7828 / 7834
页数:7
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