Evidence of the primary-color photoluminescence in ion (H+,H2+,C-) irradiated and thermal annealed SrTiO3

We have measured photoluminescence (PL) spectrum of (1) thermal-annealed SrTiO3/Si thin film and undoped SrTiO3 single crystal; (2) SrTiO3 single crystal irradiated by high energy (3 MeV) proton, deuterium, and He ion beams and (3) SrTiO3 single crystal irradiated by low energy (60 keV) H+ and C- ions. Two PL emissions are induced in (1) and (2) at visible frequencies 3 and 2.45 eV, while another PL peak is induced at 2 eV in (3). When compared with our previous PL experiments on high-temperature annealed SrTiO3/SiO2/Si thin film and 3 MeV proton (H+) irradiated STO single crystal, these results confirm that the three PL emissions with blue (3 eV), green (2.45 eV), and red-orange (2 eV) frequencies originate indeed from SrTiO3. These primary-color PL effect induced at room-temperature makes STO a strong candidate material for future oxide-based optoelectronic application.