Remarkable photocurrent in heterojunctions of n-La0.9Hf0.1MnO3/i-SrTiO3/p-Si at room temperature

Controllable manipulation for electrical transport in manganite-based heterojunctions have been desired and studied all the time due to their promising applications in electronic and spintronic devices. We report heterojunctions composed by n-type La0.9Hf0.1MnO3 and p-type Si with a SrTiO3 interlayer. The junctions reveal the formation of n-i-p junction in a wide temperature range of 20–300 K. Under illumination of 630 nm light, remarkable photocurrent has been observed. The photosensitivity (IS), defined as the ratio of photocurrent to dark current, reaches over 1200% under −3 V bias and illumination of red light with 10 mW cm−2 at room temperature. Even light power density is as low as 0.2 mW cm−2, IS is still over 200% under −1.5 V bias. The injection of photo-carriers could be responsible for the observed phenomenon. Such manipulative features by light illumination and bias should be of great potential for functional light sensors.