[16p-213-1~14] 16.1 Fundamental properties, evaluation, process and devices in disordered materials

[16p-213-11] Photoluminesence of oxygen dangling bonds in crystalline SiO₂

Linards Skuja¹, 〇Koichi Kajihara², Jurgis Grube¹, Hideo Hosono³ (1.Univ. Latvia, 2.TMU, 3.TITech)

Keywords:oxygen dangling bonds, &alpha-quartz, photoluminesence

Photoluinesence of oxygen dangling bonds (nonbridging oxygen hole centers, NBOHCs) was observed for neutron-irradiated crystalline SiO₂ (α-quartz) using time-resolved site-selective spectroscopy at 20K. NBOHCs, which are intrinsic point defects characteristic to amorphous SiO₂, were formed in amorphized regions of neutron-irradiated α-quartz and exhibited usual disorder-broadened PL band at 1.9 eV. In addition, several sharp "crystal-like" bands, whose positions do not shift with the excitation wavelength, are observed. Along with the previously reported NBOHCs with zero-phonon line (ZPL) at 1.933 eV, the second sub-type of NBOHCs with ZPL at 1.883 eV is confirmed by observation of its vibrational sideband due to Si-(dangling O) stretching mode of 897 cm^-1. The third sub-type of NBOHCs with an excitation energy at 1.879 eV, which did not exhibit ZPL whereas distinguished by a strong coupling to low-energy (66 cm^-1) vibrational mode, was found. This mode was also weakly coupled to the other two sub-types of NBOHCs.