Photoluminescence of nitrogen doped SrTiO3

Nitrogen doped SrTiO3 (N-STO) was fabricated by the ion implantation technique. The microstructure and photoluminescence (PL) of virgin N-STO and HF acid etched N-STO were studied in detail. X- ray diffraction measurements indicate that the nitrogen dopants can enhance the crystal structure of STO, and that there are no other impurity phases in N-STO except that of cubic STO. However, there is nano-crystal phase of Sr2Ti6O13 in the HF-acid-etched STO and N-STO. The room temperature PL intensity of the original STO crystal is quenched by nitrogen dopants, which might be related to the absence of trapped holes and electrons due to the enhanced crystal structure. In contrast, the room temperature PL intensity is greatly increased by HF acid etching for both STO crystal and N-STO. This increase in PL intensity may be related to the order -disorder effect and the stabilization of self-trapped excitons at room temperature due to the nano-crystal phase of Sr2Ti6O13.