Ultraviolet photoresponse properties of SrTiO₃ single crystals

¹ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, P.R. China
² Department of Mathematics and Physics, China University of Petroleum, Beijing 102249, P.R. China
³ International Center for Materials Physics, Chinese Academy of Sciences, Shenyang 110016, P.R. China

Corresponding authors: zhk@cup.edu.cn hblu@aphy.iphy.ac.cn

Received: 23 October 2006
Accepted: 26 January 2007
Published online: 22 February 2007

Abstract

We have observed ultraviolet photosensitive properties of SrTiO₃ single crystals. The photoresponse signal reaches 7.6 mV under a bias voltage of 110 V and an on-sample energy of 250 nJ for a 15-ps-duration 355 nm laser pulse. A linear relationship is obtained to the peak signal as a function of bias without any saturation trend from 1 to 110 V. Ultrafast characteristic as a function of time was also presented with the rise time as short as 750 ps. Furthermore, a weak photoresponse was detected with a large bias of 2.5 kV under a 420-nm-wavelength laser pulse due to band edge tilting, and drop three orders of magnitude than that under the 355 nm laser pulse, indicating the setup consisting of SrTiO₃ single crystal is suitable for detecting ultraviolet radiation.