Making shallow traps in barium titanate inactive by reduction

Abstract

An electron conductive BaTiO₃ crystal without shallow traps is desirable for photorefractive applications. For this report, a nominally undoped BaTi0₃ crystal was grown by the top-seeded solution method, then cut into several pieces, and these pieces were systematically reduced. By investigating the absorption spectra, the light-induced absorption changes, the two-beam coupling gain and the dark-conductivity, we found that the sample reduced at 10⁻¹² atm oxygen partial pressures to be electron conductive and the shallow traps to be inactive.