Bi-Metallic sulphides 1D Bi2S3 microneedles/1D RuS2 nano-rods based n-n heterojunction for large area, flexible and high-performance broadband photodetector

Abstract

Transition Metal Dichalcogenides based flexible photodetectors have gained importance owing to the excellent absorption and photo conductivity. However, the fabrication of layered materials requires complex processes, high thermal budget, fabrication conditions using toxic precursors with expensive experimental facilities. In this work, we report a novel combination i.e., layered bimetallic chalcogenides Bi2S3/RuS2 hybrid heterojunctions with engineered interfacial structures facilitating wide range of absorption for broadband photodetector applications. The bimetallic sulphides were grown on biodegradable cellulose paper substrate using one-step hydrothermal method and optimized to get desired 1D/1D morphology. Detailed characterization studies demonstrate the formation of 1D-Bi2S3 microneedles with an orthorhombic phase and 1D-RuS2 nano-rods with a cubic phase structure providing clear evidence of 1D/1D hybrid heterostructure formation. The fabricated photodetector displayed excellent photo response in the UV, Visible and NIR region with a maximum responsivity of 58.2 mA/W towards visible light. A maximum EQE of 78% was obtained with fast response time of 0.6, 0.4 and 0.7 s for UV, VIS and NIR light respectively, which are far more superior considering the cost-effective, scalable cleanroom free fabrication technique employed. The obtained response can be ascribed to the superior absorption property of RuS2 in the UV region and Bi2S3 in the visible and NIR region. The discrete distribution of RuS2 on the Bi2S3 device facilitates the formation of local electric fields and the contact engineering by collecting charge carriers from the Bi2S3 results in efficient separation of photogenerated charge carriers.This work demonstrates the first paper-based-bimetallic sulphides with unexplored bismuth and ruthenium complexes-based hybrid heterojunction based broadband photodetector with excellent flexibility, low cost, the strategy outlined here is ideal for various applications like wearable electronics, flexible devices, and security systems.