You are presented with multiple paper abstracts, alongside the associated literature review and chapter titles. Given the provided information, you are going to do a literature review. Please generate a coherent literature review that synthesizes the content, draws connections between different works, highlights major findings, and identifies any gaps in the existing research.

Literature Review Title: Carbon-Based Nanomaterials for Plasmonic Sensors: A Review 
Chapter Title:  As Sensitivity Enhancement Material 
1. Abstract of Cited Paper (BIB001):  The facile assembly of three-dimensional (3D) plasmonic substrates has been demonstrated. The assembly is based on the homogeneous decoration of multi-walled carbon nanotube/gold nanoparticle (CNT/AuNP) hybrid nanocomposites on a commercial polyvinylidene difluoride (PVDF) membrane, which is achieved via simple filtration. The CNT/AuNP hybrids with a unique 1D/0D structure remarkably improve the coverage and uniformity of plasmonic nanostructures on the membrane. The effective inter-particle and inter-tube coupling creates a multitude of hot spots within the probe area, and can produce a strong SERS effect. Moreover, the flexible membrane-based scaffold can efficiently collect and concentrate trace targets from large-volume sample solutions at milliliter-scale. The membrane-based SERS sensor shows high sensitivity and good reproducibility. The SERS sensor is employed to detect various molecular contaminants in aqueous samples, demonstrating its excellent field-testing capabilities for applications ranging from food safety to environmental monitoring. 
2. Abstract of Cited Paper (BIB002):  Abstract Semiconductive or metallic single wall carbon nanotubes have been deposited on gold nanoparticles monolayer and used as plasmonic based gas sensor. The coupling between carbon nanotubes and gold nanoparticles has the aim of combining the reactivity of the carbon nanotubes towards hazardous gases, such as H 2 , CO, NO 2 , with the localized surface plasmon resonance of gold nanoparticles, which it is known to be extremely sensitive to the changes in the dielectric properties of the surrounding medium, a working mechanism used for sensor devices. Two different techniques, ink-jet printer and dropcasting, were used for depositing the transparent carbon nanotubes film on the plasmonic layer. Ink-jet printed metallic single wall carbon nanotubes showed high sensitivity toward H 2 at low operative temperature with the detection of low concentration of H 2 . On the contrary, the semiconductive single wall carbon nanotubes displayed very poor gas sensing properties. 
3. Abstract of Cited Paper (BIB003):  Abstract In this work, a functional nanocomposite consisting of silver nanoparticles and multiwalled carbon nanotubes (MWCNTs-Ag) was successfully synthesized using a two-step chemical process. The MWCNTs-Ag nanocomposite has been studied as a surface-enhanced Raman scattering (SERS) sensing platform for detection of methylene blue (MB) dye in an aqueous medium. The obtained results reveal that the MWCNTs-Ag nanocomposite exhibits higher SERS detection activity than that of pure Ag-nanoparticles (Ag-NPs). The calculated enhancement factors are 1.51 × 106 for pure Ag-NPs and 4.68 × 106 for the MWCNTs-Ag nanocomposite. MB detection has been achieved as low as 1 ppm. The SERS enhancement of the MWCNTs-Ag nanocomposite can be attributed to the combination of both an electromagnetic (EM) effect and a chemical effect (CE). With exhibited properties, the MWCNTs-Ag nanocomposite can be effectively used for detection of various organic dyes in water solution.

Literature Review:
Carbon-based nanomaterials, specifically graphene and carbon nanotubes, are widely known to be sensitivity enhancement materials for plasmonic sensors BIB001 BIB003 . Therefore, they are extensively reported in SERS signal enhancement substrates due to plasmon coupling with metal nanoparticles BIB002 BIB004 . However, we have constrained ourselves here to discussing only the SPR-based biosensors for sensitivity enhancement due to these carbonaceous materials. Carbon-based nanomaterials, specifically graphene and carbon nanotubes, are widely known to be sensitivity enhancement materials for plasmonic sensors BIB001 BIB003 . Therefore, they are extensively reported in SERS signal enhancement substrates due to plasmon coupling with metal nanoparticles BIB002 BIB004 . However, we have constrained ourselves here to discussing only the SPR-based biosensors for sensitivity enhancement due to these carbonaceous materials.