Atomic-level 2-dimensional chemical mapping and imaging of individual dopants in a phosphor crystal

Abstract

The ability to visualize and identify individual dopants, as well as measure their local physical and chemical environments in a bulk, provides deep insight for designing new functional materials and predicting their properties. However, a full understanding of dopants inside a solid has been limited by currently available characterization techniques. We demonstrate the first atomic-level 2-dimensional elemental maps of Pr dopants using the electron energy-loss spectroscopy (EELS) technique and we image Al dopants located in a lattice. Based on spectroscopic and imaging evidence we provide plausible local defect configurations of implanted Pr(+) and Al(+) ions within SrTiO3 single crystals. Our results demonstrate the detection of single Pr atoms and the formation of Al-rich nanoscale clusters ranging from 1 to 3 nm in size randomly distributed in the implanted lattice. These results provide insight into the mechanism of red light emission in doped SrTiO3.