Unusual ultraviolet photoconductivity in single crystalline SrTiO3.

In this paper, ultraviolet photoconductivity of single crystalline SrTiO(3) is studied. It is found that the photoconductivity of SrTiO(3) arises from intrinsic band-to-band excitation, and photoconductivity increases monotonously with decreasing temperature and undergoes six or seven orders of magnitude enhancement from room temperature to 10 K. In particular, at and below 105 K, the structural transition temperature, SrTiO(3) is highly ultraviolet-sensitive, and the photoconductivity increases drastically so that a TCR (temperature coefficient of resistance) ∼30% is observed. Moreover, it is the first time that an anomaly is observed in photoconductivity at around 65 K and 37 K respectively. These results will shed light on our understanding of the band structure of tetragonal-phase SrTiO(3), and the physics of SrTiO(3) at lower temperatures.