Giant photothermoelectric effect in silicon nanoribbon photodetectors

Wei Dai; Weikang Liu; Jian Yang; Chao Xu; Alessandro Alabastri; Chang Liu; Peter Nordlander; Zhiqiang Guan; Hongxing Xu

doi:10.1038/s41377-020-00364-x

Giant photothermoelectric effect in silicon nanoribbon photodetectors

Light Sci Appl. 2020 Jul 14:9:120. doi: 10.1038/s41377-020-00364-x. eCollection 2020.

Authors

Wei Dai^#¹, Weikang Liu^#¹, Jian Yang^#², Chao Xu¹, Alessandro Alabastri², Chang Liu¹, Peter Nordlander², Zhiqiang Guan¹, Hongxing Xu^{1

3}

Affiliations

¹ School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan, 430072 China.
² Department of Physics and Astronomy, Department of Electrical and Computer Engineering and Laboratory for Nanophotonics, Rice University, Houston, TX 77005 USA.
³ The Institute for Advanced Studies, Wuhan University, Wuhan, 430072 China.

^# Contributed equally.

Abstract

The photothermoelectric (PTE) effect enables efficient harvesting of the energy of photogenerated hot carriers and is a promising choice for high-efficiency photoelectric energy conversion and photodetection. Recently, the PTE effect was reported in low-dimensional nanomaterials, suggesting the possibility of optimizing their energy conversion efficiency. Unfortunately, the PTE effect becomes extremely inefficient in low-dimensional nanomaterials, owing to intrinsic disadvantages, such as low optical absorption and immature fabrication methods. In this study, a giant PTE effect was observed in lightly doped p-type silicon nanoribbons caused by photogenerated hot carriers. The open-circuit photovoltage responsivity of the device was 3-4 orders of magnitude higher than those of previously reported PTE devices. The measured photovoltage responses fit very well with the proposed photothermoelectric multiphysics models. This research proposes an application of the PTE effect and a possible method for utilizing hot carriers in semiconductors to significantly improve their photoelectric conversion efficiency.

Keywords: Electronics, photonics and device physics; Optics and photonics.