Abstract

When crystals are doped with aliovalent ions, defects are formed to balance the charge mismatch. Many defect structures can form from different combinations of the dopant and charge compensating ions. Site selective spectroscopy can be used to selectively examine specific structures using fluorescent dopant ions whose crystal field splittings reflect the local environment. The fluorescence is used to measure absolute site concentrations, and follow the concentrations as the crystals are modified by changing dopants, concentrations, crystal temperature, or the partial pressure of equilibrating gases. The individual defect sites can be identified and the distribution of different defects can be described by models of the solid state chemistry. The dynamics of defect formation can also be followed to acquire a detailed microscopic description of the defects. Sites with particularly favorable optical properties (radiative transition rates, energy transfer, quantum efficiency, etc.) can be optimized by appropriate processing conditions.

© 1989 Optical Society of America