Conduction mechanism and temperature-dependent current-voltage in (Ba, Sr)TiO3 thin films

Abstract

RF magnetron sputtered (Ba, Sr)TiO3 (BST) thin films were deposited on Pt/SiO substrate with various O-2/(O-2 + Ar) mixing ratios (OMR) ranging from 0 to 60%. Two possible conduction mechanisms of the BST thin films, the Poole-Frenkel (PF) transport (bulk limited conduction) and the Schottky emission (SE) (electrode limited conduction) were studied. Experimental results indicated that the BST films prepared at low OMR (0-25%) exhibit the SE mechanism dominated below the transition electric field of 490 kV/cm and the PF transport mechanism dominated beyond 490 kV/cm; and while those prepared at high OMR (40-60%) display the SE mechanism dominated both below and beyond the transition electric field. The difference in dominant mechanism (bulk and electrode limited conduction) between films was ascribed to concentration variation of the oxygen vacancy in the films.