An in-house-built thermally stimulated current measurement setup: Strontium titanate as a test system

A semiautomated thermally stimulated current (TSC) measurement setup was developed in-house, which is capable of measuring low currents (<10(-15) A) in a wide temperature range. This setup was used to study defects (bulk traps) in strontium titanate ceramics and single crystals. Strontium titanate was chosen as a test system because of the availability of data in the literature. Analysis of the TSC curves using various methods revealed traps with activation energies of approximately 0.64 eV and 0.80 eV. which can be attributed to acceptor impurities in single crystal and undoped SrTiO3, respectively In polycrystalline SrTiO3 doped with 0.5, 1.0 and 1.5 mole% Nb2O5, traps with activation energy of similar to 0.45 eV were found. These traps are believed to arise from Nb2O5 dissolved in the SrTiO3 matrix, as confirmed by scanning electron microscope with energy dispersive X-ray spectrometry (SEM/EDX) and electrical conductivity measurements.