Unusual Electrical Transport Characteristic of the SrSnO3/Nb-Doped SrTiO3 Heterostructure

Abstract

An all-perovskite oxide heterostructure composed of SrSnO 3 /Nb-doped SrTiO 3 was fabricated using the pulsed laser deposition method.In-plane and out-of-plane structural characterization of the fabricated films were analyzed by x-ray diffraction with θ-2θ scans and φ scans.X-ray photoelectron spectroscopy measurement was performed to check the film's composition.The electrical transport characteristic of the heterostructure was determined by applying a pulsed dc bias across the interface.Unusual transport properties of the interface between the SrSnO 3 and Nb-doped SrTiO 3 were investigated at temperatures from 100 to 300 K.A diodelike rectifying behavior was observed in the temperature-dependent current-voltage (IV) measurements.The forward current showed the typical IV characteristics of p-n junctions or Schottky diodes, and were perfectly fitted using the thermionic emission model.Two regions with different transport mechanism were detected, and the boundary curve was expressed by ln I = -1.28V-13.Under reverse bias, however, the temperature-dependent IV curves revealed an unusual increase in the reverse-bias current with decreasing temperature, indicating tunneling effects at the interface.The Poole-Frenkel emission was used to explain this electrical transport mechanism under the reverse voltages.