High-sensitivity photovoltaic responses in manganite-based heterojunctions on Si substrates for weak light detection.

We have fabricated and characterized a weak light photodetector in a heterojunction composed of manganite La0.4Ca0.6MnO3 and n-type Si. High-sensitivity photoresponse properties were investigated. The responsivities of open-circuit photovoltage and short-circuit photocurrent reach ∼1000  V/mJ and ∼30  A/mJ, respectively, without any amplification bias under irradiation by 20-ps-wide and 355, 532, and 1064-nm-wavelength laser pulses in nanojoule to microjoule order. The present results demonstrate that the manganite-based heterojunction on Si substrate has potential applications in weak light detection from ultraviolet to near-infrared light.