Surface morphology and dielectric behavior of perovskite SrTiO3 thin film in heterostructure electroluminescence devices

Epitaxial SrTiO3 thin film was grown on 1%-Nb-doped SrTiO3 (001) substrate by pulsed laser deposition (PLD). Post-annealing at 1050 °C drastically changes the particle-type surface morphology of the as-grown film to a well-defined step-terrace structure. An atomically smooth surface was obtained with a step height of about 0.4 nm, which corresponds to one-unit-cell of SrTiO3 (a = 0.3905 nm). The dielectric constants εr at 300 and 2 K were found to be 120 and 520 at 100 kHz, respectively. The dielectric losses at 300 and 2 K were 2.0 × 10−5 and 1.2 × 10−5 at 100 kHz, respectively. Temperature dependence of the dielectric properties showed suppressed quantum paraelectricity. Post-annealed films with an atomically smooth surface used as an insulating layer contribute to the high performance of thin-film electroluminescent (TFEL) heterostructure devices. Preparation of ideal interfaces of different materials may aid in the development of heterostructure electronic devices.