Synthesis and electrical characterization of bismuth ferrite thin films

Official URL: http://192.168.1.20/record=b1493305 (Table of Contents)

Pure single phase BiFeO3 and Gd doped BiFeO3 with different Gd doping levels were synthesized through a metalorganic route. Quasi-epitaxial (columnar) BiFeO3 films were fabricated on the top of SrTiO3 substrates with preferred orientation. The rectifying properties of Nb:SrTiO3-BiFeO3-Pt structures, in which the BiFeO3 layer was doped with Gd (0 %; 5 %; and 10 %), were investigated by measuring current-voltage characteristic at different temperatures. It was found that the structures show a diode-like behavior with reverse bias for negative polarity and forward bias for positive polarity applied on the top Pt contact. The potential barrier was estimated for negative polarity assuming a Shottkylike thermionic emission with injection controlled by the interface and the drift controlled by the bulk. It was found that the height of the potential barrier is dependent on the Gd doping, being 0.32 eV for zero doping, 0.45 eV for 5 % doping and 0.60 eV for 10 % doping. The result is explained by the partial compensation of the p-type conduction induced by Bi volatility with Gd doping. The Fermi level moves upward as the doping concentration increases leading to a higher potential barrier for holes.