Visible-Light-Driven Semiconductor–Metal Transition in Electron Gas at the (100) Surface of KTaO<sub>3</sub>
Xiaochen Tian,
Bocheng Li,
Hu Sun,
Yucheng Jiang,
Run Zhao,
Meng Zhao,
Ju Gao,
Jie Xing,
Jie Qiu,
Guozhen Liu
Affiliations
Xiaochen Tian
Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China
Bocheng Li
Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China
Hu Sun
Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China
Yucheng Jiang
Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China
Run Zhao
Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China
Meng Zhao
Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China
Ju Gao
Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China
Jie Xing
School of Science, China University of Geosciences, Beijing 100083, China
Jie Qiu
Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China
Guozhen Liu
Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China
Two-dimensional electron gas (2DEG) at the (100) KTaO3(KTO) surface and interfaces has attracted extensive interest because of its abundant physical properties. Here, light illumination-induced semiconductor–metal transition in the 2DEG at the KTO surface was investigated. 2DEG was formed at the surface of KTO by argon ion bombardment. The 2DEG prepared with a shorter bombardment time (300 s) exhibits semiconducting behavior in the range of 20~300 K in the dark. However, it shows a different resistance behavior, namely, a metallic state above ~55 K and a semiconducting state below ~55 K when exposed to visible light (405 nm) with a giant conductivity increase of about eight orders of magnitude at 20 K. The suppression of the semiconducting behavior is found to be more pronounced with increasing light power. After removing the illumination, the resistance cannot recover quickly, exhibiting persistent photoconductivity. More interestingly, the photoresponse of the 2DEG below 50 K was almost independent of the laser wavelength, although the photon energy is lower than the band gap of KTO. The present results provide experimental support for tuning oxide 2DEG by photoexcitation, suggesting promising applications of KTO-based 2DEG in future electronic and optoelectronic devices.
