Surface Engineered 2D TMD Materials for Advanced Wearable Biosensors

In the past decade, the 2D materials-based electronic products market is rapidly growing especially in the areas of sensing, energy storage, biomedical, or ultrafast optoelectronics. Out of many 2D materials, transition-metal-dichalcogenides (TMDs) are one of the promising 2D materials which have weak van der-Waals force between each covalently bonded layer (X-M-X) of transition metals (M) and chalcogens (X). These individual-layer of TMDs undergo the transition from in-direct to direct band gap and have remarkable and fascinating electronic and optical properties. Moreover, TMDs have tremendous potential in several applications such as light emission, photodetection, gas sensing, biosensors, bio-imaging, and drug delivery because of their high density of surface sites. Furthermore, TMDs also act as associative biosensing elements for the real-time detection of biomarkers and, hence, exhibit great potential in biosensors and healthcare devices. The surface engineering and modification of TMDs can further enhance their electronic and sensing properties. Therefore, understanding the interfacial properties and atomic structures, and surface engineering of TMDs are thus of significant importance for the advancement of biosensors. The presented book chapter, comprehensively discusses the several deposition techniques for TMDs, their advantages, and disadvantages, the growth quality of deposited thin layers of TMDs, their morphological and structural analysis, several parameters for performance analysis of fabricated 2D-TMDs-based wearable biosensors and the effect of surface modification on device sensitivity, selectivity, and responsivity. Here, the various challenges and their solutions during bandgap tuneability and functionalization with various opportunities for application in advanced wearable biosensors have been discussed.