Photoluminescence of perovskite lanthanum aluminate single crystals

Photoluminescence was observed from pure perovskite lanthanum aluminate $({\mathrm{LaAlO}}_3)$ single crystals grown with a floating-zone method in reduced atmosphere. Emission was composed of a fast ultraviolet (UV) component and a broad visible emission with a lifetime of 13 μs. From the lifetime measurement, absorption spectra, excitation spectrum, and comparison between samples as-grown and annealed in oxygen, we assigned the UV emission to band-to-band emission or emission from polaron pairs. The visible component was assigned to emission from the excited state formed at oxygen defect sites. These emissions demonstrate the possibility of light-emitting devices made of perovskite oxides.