Influence of chemical nature of implanted atoms on photoluminescence of ion-synthesized 9R-Si hexagonal silicon

To use silicon in emerging photonic devices, it is necessary to improve its luminescent properties. In this regard, hexagonal modifications of silicon are attracting great attention, as they demonstrate an increased emissivity in comparison with cubic silicon. It has been recently established that, upon irradiation of the SiO2/Si structure with Kr+ ions, a photoluminescence line appears, which is associated with the formation of the 9R-Si hexagonal phase. In this work, we compare the changes in photoluminescence under irradiation with As+ and Kr+, which are close in atomic mass and radius but differ in chemical nature. Irradiation and subsequent annealing were carried out under identical conditions with ion energy of 80 keV, dose of 5·1016 cm−2 and annealing temperature of 800 °C (30 min in N2). It is found that photoluminescence line at around 1240 nm is observed in both cases, but the intensity is significantly higher and the maximum is shifted by 5 nm towards shorter wavelengths for As+ irradiation compared to Kr+ irradiation. The results are interpreted taking into account the different degree of out-diffusion of As and Kr associated with their different chemical nature.