Different behaviors of F+ centers due to electron beam irradiations between synthetic sapphire and Be-diffusion-treated natural sapphire

Electron-beam irradiation effects on luminescence properties in subsurface regions of single-crystalline sapphires treated with and without hydrogen plasma exposures

“…1(a)). As previously reported [12], such increases in the CL intensities with increasing the electron fluences were represented roughly by exponentially saturating curves. The CL intensity variation curves thus fitted were shown by thin solid lines in Fig.…”

“…Fluence dependence of electron-beam-irradiationinduced CL spectral changes At first, we investigated possible effects of annealing in the air, annealing in vacuum and H-plasma exposures on Since the F + -center CL intensity peaked at E330 nm (E3.7-3.8 eV) was found to be sensitive to the electron beam irradiations [12], the electron fluence dependence of the F + CL intensity was measured under the continuous electron irradiations. Although the irradiation electron energy of 15 keV may be too low to displace oxygen, an F + center can be formed by one O vacancy trapped with an electron, which is supplied by the incident electron beam.…”

“…However, it is known that electron beam irradiations to sapphire can change oxygen vacancies to F + and F centers, which are common luminescence centers in various oxide materials composed of oxygen vacancies with one trapped electron and two captured electrons, respectively [10,11]. In previous studies, we have found that such electron-irradiation-induced behaviors substantially depend on the type of the sapphire and crystalline quality [12,13]. It is also understood that some characteristic luminescence peaks of sapphire originate from the F + and F centers and impurity-metal-related centers [14].…”

“…Until now, we have reported some irradiation effects of keV electrons on the luminescence centers and optical properties of various types of natural and synthetic sapphires [12,13]. In the present study, we have investigated the electron-fluence dependence of the irradiation-induced effects for Be-diffused natural orange sapphire (BNS), synthetic orange sapphire (SOS, grown by Verneuil method) and synthetic substrate sapphire (SSS, grown by Czochralski method).…”

The study of optical property of sapphire irradiated with 73 MeV Ca ions

“…Its properties can be modified by point defects or extended defects produced by different type particle irradiation, such as electron, neutron and ion [4][5][6][7][8]. Due to its versatility [9,10], ion implantation or irradiation is the most favorable method used to modify the optical properties of sapphire.…”