Ouyang Bangsen, Zhang Kewei, Yang Ya
CAS Center for Excellence in Nanoscience, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083, P. R. China; School of Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
CAS Center for Excellence in Nanoscience, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083, P. R. China; School of Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
iScience. 2018 Mar 23;1:16-23. doi: 10.1016/j.isci.2018.01.002. Epub 2018 Jan 31.
Self-powered photodetectors are expected to play a crucial role in future nano-optoelectronic devices owing to their independent and sustainable operation. Based on the heterojunction between ZnO nanowires (NWs) and shuttle-like SnS, we design a self-powered photodetector exhibiting wide-range photoresponse and tunable spectral selectivity. Differently from conventional devices, a wavelength-induced photocurrent polarity is observed in the ZnO NWs/SnS photodetector, which enables the device to distinguish between photons in the UV and visible (VIS) regions. This is due to switching of the interfacial modulation by the pyroelectric-polarization potential (pyro-potential) inside ZnO NWs and thermoelectric-polarization potential (thermo-potential) inside SnS. A photocurrent enhancement of 125% and improved responsivity of 364 μA/W are obtained under the pyro-potential upon 690 nm light illumination, whereas reversed responsivity of -155 μA/W is obtained under the thermo-potential upon 365 nm light illumination. We believe the photocurrent polarity could be useful for improving resolution of dynamic light sensing/imaging.
自供电光电探测器因其独立且可持续的运行方式，有望在未来的纳米光电器件中发挥关键作用。基于氧化锌纳米线（NWs）与梭形硫化锡之间的异质结，我们设计了一种具有宽范围光响应和可调光谱选择性的自供电光电探测器。与传统器件不同，在氧化锌纳米线/硫化锡光电探测器中观察到了波长诱导的光电流极性，这使得该器件能够区分紫外光（UV）和可见光（VIS）区域的光子。这是由于氧化锌纳米线内部的热释电极化电势（热电势）和硫化锡内部的热电极化电势对界面调制的切换所致。在690nm光照下，热电势作用下光电流增强了125%，响应度提高到364μA/W，而在365nm光照下，热电势作用下反向响应度为-155μA/W。我们认为光电流极性可能有助于提高动态光传感/成像的分辨率。
