Studying of two-dimensional interfacial interactions
- UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
- Sajedeh Pourianejad (Creator)
- Institution
- The University of North Carolina at Greensboro (UNCG )
- Web Site: http://library.uncg.edu/
- Advisor
- Tetyana Ignatova
Abstract: Two-dimensional (2D) materials and their van der Waals (vdW) heterojunctions offer the opportunity to combine layers with different opto-electrical properties to advance novel functional materials. Heterostructures comprised of graphene and 2D MoS2 is a realized contender for a wide range of optoelectronic devices. This is owing to graphene’s high transparency and configurable Fermi level, as well as the tunability of 2D MoS2 ‘s photoluminescent (PL) properties. In this dissertation, we investigated 2D interfacial interactions such as: graphene in contact with different polymers, 2D MoS2 with external doping, and the lateral charge redistribution created by the graphene - MoS2 heterojunction. For this purpose, we studied the adhesion properties of graphene and its transfer support polymer, which led to the development of a modified polymer support. In addition, we fabricated graphene and 2D MoS2 heterostructures and evaluated the magnitude and direction of the internal charge transfer (i.e., electron or hole). Furthermore, we studied the influence of external doping on 2D MoS2, which resulted in PL enhancement. Moreover, we examined local nanometer scale non-uniformities of graphene-MoS2 heterostructures, which led to the development of a multimodal biosensor for detecting doxorubicin (DOX). The optical and electronic structure of the materials, as well as doping and strain configuration, were probed by Confocal Raman microscopy and photoluminescence. The surface morphology of 2D MoS2 and graphene were imaged by scanning electron microscopy (SEM). To correlate the work function difference to charge-related phenomena, Kelvin probe force microscopy (KPFM) was carried out. We quantified the effect of local charge and defect distribution on the characteristics of 2D materials and this led to the fabrication of a device that has biosensing applications. Such 2D optical devices have the potential to become ultra-small sensing platforms, making major contributions to medical diagnosis and treatment; pollution control; and safety control.
Studying of two-dimensional interfacial interactions
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Created on 5/1/2022
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Additional Information
- Publication
- Dissertation
- Language: English
- Date: 2022
- Keywords
- 2D materials
- Subjects
- Two-dimensional materials
- Molybdenum disulfide
- Graphene