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Full-Text Articles in Physics

Near-Field And Far-Field Microscopic And Spectroscopic Characterizations Of Coupled Plasmonic, Excitonic And Polymeric Materials, Chih-Feng Wang Nov 2019

Near-Field And Far-Field Microscopic And Spectroscopic Characterizations Of Coupled Plasmonic, Excitonic And Polymeric Materials, Chih-Feng Wang

Optical Science and Engineering ETDs

The properties of localized surface plasmons (LSP) have been broadly utilized for chemical sensing, surface enhanced Raman spectroscopy, biomedical imaging and photothermal treatments. By exploiting well-established plasmonic effects, the spectroscopic investigation of intriguing quantum phenomena, such as excitonic interband and intersubband (ISB) transitions in semiconductor heterostructures, was examined and extended in both far- and near-field optical measurements. For far-field characterization, we used colloidal plasmonic Au nanorods (AuNRs) to increase the quantum efficiency of InGaAs/GaAs single quantum well. By analyzing the temperature-dependent photoluminescence enhancement as a function of GaAs capping layer thickness, we attributed the mechanism of the LSP enhancement to …


Tip-Enhanced Nano-Optical Imaging Of Superacid Treated Bilayer Mos2-Ws2 2d Lateral Heterostructures, Amala Dixit Mar 2019

Tip-Enhanced Nano-Optical Imaging Of Superacid Treated Bilayer Mos2-Ws2 2d Lateral Heterostructures, Amala Dixit

USF Tampa Graduate Theses and Dissertations

Nanoscale optical characterization of two-dimensional (2D) materials and heterostructures is important for the design of novel optoelectronic flexible nano-devices. Nano-optical photoluminescence (PL) and Raman imaging of bilayer 2D materials has been a challenging problem due to weak signals. The exciton-dominated light emission of two-dimensional (2D) transition metal dichalcogenide (TMDC) materials is affected by the formation of defects and doping states. Previous studies have shown that chemical treatment modifies the defect and doping states of chemical vapor deposition (CVD)-grown monolayers of MoS2 and WS2, which provides a promising possibility for engineering the optoelectronic properties of these 2D TMDCs. …


Probing Quantized Excitations And Many-Body Correlations In Transition Metal Dichalcogenides With Optical Spectroscopy, Shao-Yu Chen Mar 2019

Probing Quantized Excitations And Many-Body Correlations In Transition Metal Dichalcogenides With Optical Spectroscopy, Shao-Yu Chen

Doctoral Dissertations

Layered transition metal dichalcogenides (TMDCs) have attracted great interests in recent years due to their physical properties manifested in different polytypes: Hexagonal(H)-TMDC,which is semiconducting, exhibits strong Coulomb interaction and intriguing valleytronic properties; distorted octahedral(T’)-TMDC,which is semi-metallic, is predicted to exhibit rich nontrivial topological physics. In this dissertation,we employ the polarization-resolved micron-Raman/PL spectroscopy to investigate the optical properties of the atomic layer of several polytypes of TMDC. In the first part for polarization-resolved Raman spectroscopy, we study the lattice vibration of both H and T’-TMDC, providing a thorough understanding of the polymorphism of TMDCs. We demonstrate that Raman spectroscopy is a …