Exfoliated Se nanoparticles decorated on MoS2/paper-based heterojunction as a flexible, self-powered and highly responsive photodetector

Abstract

Self-powered heterostructure based photodetectors are of great research interest owing to their zero-power consumption, enhanced light-matter interaction, and the ability to respond in harsh environmental conditions. Selenium (Se) nanoparticles have been recently explored in photodetectors due to their high absorption coefficient and superior light-sensing ability. However, most reported Selenium based photoconductors utilize sophisticated device fabrication methodology, requiring regulated environmental conditions, elevated temperature and face flexibility issues. This work demonstrates a discrete(localized) heterojunction of exfoliated Selenium decorated on hydrothermally grown MoS2/paper-based high-performance, flexible, and self-powered photodetector. X-ray Diffraction and Raman Spectroscopy studies reveal the presence of hexagonal Se and the SEM image shows the uniformly grown MoS2 on cellulose paper. It also confirms the presence of Se clustered nanoparticles. The hybrid heterostructure device displays broadband response in the Vis-NIR region. Upon light illumination, a built-in field is generated due to the efficient separation of the charge carriers, making the fabricated device to operate at zero bias. The as-fabricated device exhibits superior responsivity of 0.14 A/W and 0.49 A/W and detectivity of 4.55 × 1011 Jones (intensity- 35.8 mW/cm2) and 5.01 × 1010 Jones (intensity- 30.08 mW/cm2) upon Vis and NIR irradiation, respectively, at no bias. This superior performance is asserted to the peak absorption of Se nanoparticles in the NIR region. The device also showed superior resistance to bending stress and retained its original characteristics even after multiple bending cycles (∼1050). Hence, with this facile device fabrication and simple device architecture strategy, this work paves the way for developing high-performance tensile photodetectors.