Rectifying characteristics and photovoltaic effect in heterojunctions of La0.9Sr0.1MnO3/Nb-doped SrTiO3

Heterojunctions were fabricated by depositing La0.9Sr0.1MnO3 (LSMO) films on 0.8wt% Nb-doped SrTiO3 substrates. Such heterojunctions showed good rectifying characteristics and clear photovoltaic effect. When the temperature increases from 50K to room temperature, the diffusion voltage (Vd) decreases from 0.77to0.22V and the photovoltage Voc monotonically dropped from 2to1mV. No sudden change of Vd or Voc was observed at the metal-insulator transition temperature, which differs from the previous works. This is probably caused by of the difference between the band structure of LSMO and the manganites used in previous works.