Reduction of Native Singly Ionized Zinc Vacancies Content by 2.5 MeV Electron Irradiation of ZnGeP₂ Single Crystals

An experimental study on how to reduce the content of singly ionized zinc vacancy (V⁻_Zn) in ZnGeP₂ crystals to improve their optical quality is presented. Their electron paramagnetic resonance signal has been studied in samples treated in different ways. The data provide a scheme of the reductions that can be obtained by the different methods or by their combinations. The adding of Sn during the synthesis phase helps the production of large-size single crystals and the reduction of the V⁻_Zn content. Thermal treatment and electron irradiation are then needed for further reduction. At the fluence of 2 × 10¹⁷ e cm⁻², the V⁻_Zn decrease does not reach a minimum value, so with higher fluences, additional reduction of V⁻_Zn content is expected.