Manipulation of reverse bias transport by photocarrier injection in Pr0.7Ca0.3 MnO3??/SiO2/Si heterojunction.

A Pr0.7Ca0.3MnO3[?]d/SiO2/Si heterojunction with good rectifying property is fabricated. An interesting phenomenon observed in these heterojunctions is that electrical transport under reverse bias is sensitive to light illumination, while that under forward bias is insensitive. The photoinduced resistance ratio can even reach [?]93.8% with a reverse bias I = 0.04 uA and is always over 75% within the whole measured current range as the light power density P = 0.3 mW cm[?]2 at T = 200 K. The observed phenomenon is discussed according to the effect of photocarrier injection to the junction under different direction bias voltages. [ABSTRACT FROM AUTHOR]