Temperature-dependent photovoltage response in La0.9Li0.1MnO3/SrTiO3-Nb heterojunction induced by a low intensity pulse laser

The photovoltage response under low intensity pulse laser (473 nm) in the perovskite manganite p-n junction La0.9Li0.1MnO3/SrTiO3:Nb is investigated within a wide temperature range. The maximum photovoltage occurs at around the metal-insulator transition temperature (TMI, ~250 K) of La0.9Li0.1MnO3 rather than the lowest temperature, which indicates that the low density charge induced by a weak light can be significantly affected by the leakage rather than the thermal carriers. Moreover, the time response of photovoltage shows distinct temperature-dependent and light intensity-dependent regularities in the temperature regions TTMI respectively. The mechanisms are discussed according to the charge transport and magnetic phase transition of La0.9Li0.1MnO3.