Room-temperature persistent photoconductivity of KTaO₃

This dataset contains IR spectra of potassium tantalate (KTO3). KTaO3 single crystals annealed in hydrogen exhibit room temperature persistent photoconductivity (PPC). The oxygen-poor annealing environment creates oxygen vacancies that are substituted with hydrogen. A photon of energy near the indirect band gap (3.65 eV) can excite this defect, resulting in free electrons in the conduction band. This causes an increase in n-type conductivity of 4 orders of magnitude with a recovery time of 2-4 years. Hydrogen leaves the O site and forms an O–H bond that is observed by IR spectroscopy. In addition to the O-H peak, the IR spectra contain information about free-carrier absorption.