Fast and Low-Cost Synthesis of MoS2 Nanostructures on Paper Substrates for Near-Infrared Photodetectors

Daniela Nunes,Neusmar J. A. Cordeiro,Maria J. de Oliveira,Sidney A. Lourenço,Luís Pereira,Elvira Fortunato,Rodrigo Martins,Pedro Barquinha,Cristina Gaspar,Edson Laureto

doi:10.3390/app11031234

Abstract

Recent advances in the production and development of two-dimensional transition metal dichalcogenides (2D TMDs) allow applications of these materials, with a structure similar to that of graphene, in a series of devices as promising technologies for optoelectronic applications. In this work, molybdenum disulfide (MoS2) nanostructures were grown directly on paper substrates through a microwave-assisted hydrothermal synthesis. The synthesized samples were subjected to morphological, structural, and optical analysis, using techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman. The variation of synthesis parameters, as temperature and synthesis time, allowed the manipulation of these nanostructures during the growth process, with alteration of the metallic (1T) and semiconductor (2H) phases. By using this synthesis method, two-dimensional MoS2 nanostructures were directly grown on paper substrates. The MoS2 nanostructures were used as the active layer, to produce low-cost near-infrared photodetectors. The set of results indicates that the interdigital MoS2 photodetector with the best characteristics (responsivity of 290 mA/W, detectivity of 1.8 × 109 Jones and external quantum efficiency of 37%) was obtained using photoactive MoS2 nanosheets synthesized at 200 °C for 120 min.

Highlights

Since its discovery in 2004, graphene has become one of the nanomaterials of great interest in the construction of devices, due to its high electronic conductivity, mechanical flexibility, and low production cost [1]
The microwave-assisted hydrothermal synthesis method was used for the direct growth of MoS2 nanostructures on cellulose paper substrates due to the ease of the technique’s application, as well as its ability to change synthesis parameters to optimize the produced structures [29,30,31]
Variations were observed in the amount of MoS2 grown on top of cellulose fibers as a function of the synthesis parameters

Summary

Introduction

Since its discovery in 2004, graphene has become one of the nanomaterials of great interest in the construction of devices, due to its high electronic conductivity, mechanical flexibility, and low production cost [1]. Despite the good results obtained with graphene [2,3], the absence of energy bandgap restricts its application in some devices, such as photodetectors, mostly due to low intrinsic responsivity This led to the development of a series of other two-dimensional materials with different characteristics, such as the hexagonal boron nitride [4], silicene [5], borophene [6], black phosphourous [7], and two-dimensional transition metal dichalcogenides (2D TMDs) [8]. The bandgap of the MoS2 increases with the decrease of the crystal thickness, to below 100 nm, due to the quantum confinement effect [15], and reaches 1.89 eV for a single monolayer [13] It can cover an extent NIR (near-infrared) electromagnetic spectrum (6560 to 10,332 nm) by changing the monolayer number. The relationship between its optical and electrical characteristics with the number of stacked layers and the control of the 1T and 2H phases turns the MoS2 into a material of great interest for applications in chemical sensors [17], hydrogen evolution reaction [18], electronic devices [19], sodium-ion battery [20], and photodetectors [21,22]

Methods

Results

Conclusion