Effect of film thickness on interfacial barrier of manganite-based heterojunctions

Interfacial barrier is a key factor that determines the performances of heterojunctions. In this work, we study the effect of manganite film thickness on the effective interfacial barrier for La_0.67Sr_0.33MnO₃/Nb:SrTiO₃ junctions. The barrier is extracted from the forward current--voltage characteristics. Our results demonstrate that the barrier decreases gradually from ～0.85 eV to ～0.60 eV when the film thickness decreases from 150 nm to 2 nm. The overall value of the barrier is only about 50% of the corresponding one determined from the photovoltaic effect.