Debaleena Majumder1
Indian Institute of Science (IISc)1
Debaleena Majumder1
Indian Institute of Science (IISc)1
Various Graphene-plasmonic nanoparticle hybrid devices have paved a way for sensitive photodetection of UV signal leading to multipurpose electrical as well as optoelectronic applications. A single monolayer of graphene (SLG) is sensitized with silver nanoparticles (having size distribution of 50-100nm), such that the electric field close to the nanoparticles generated due to the Localized Surface Plasmon Resonance (LSPR) results in an increased engineered photo response in the UV spectrum. Addition of an intermediate h-BN monolayer to such photodetectors aims to improve the photo response by reducing the substrate effects, interfacial resistance along with the prevention of surface oxidation. The purpose of this study is to investigate the role of 8 different 2d material based composite nanostructures fabricated using layer-by-layer build up technique, which play a determining role in controlling their optical and electronic response.<br/>Raman Spectroscopy analyses the effect of inherent strain and local doping concentration of the graphene monolayer in presence of plasmonic structures. Full width half maxima (FWHMs) of both G and D peak are higher indicating localised strain in case of samples having Gr layer transferred on top of the Ag particles. Whereas the ID/IG ratio when much greater than 1 denotes higher defect concentration in samples due to the formation of sp3 carbon within graphene. Henceforth, significant enhancement is observed in Raman peak intensity with the introduction of HBN to the Gr-Ag composites.<br/>The Responsivity study on such samples suggest that the position of the 2D material plays a key role in the anomalous response of these detectors. Further a correlation between optical Responsivity and Resonance plasmonic peak positions with particle distribution and shape analysis was established. Subsequently, each photo response has been deconvoluted into their characteristic rise and fall time zones using an empirical formulation, from which an idea about the effect of intermediate trapping and de-trapping states of these devices can be understood.