Your browser does not support JavaScript!

Home    Search  

Results - Details

Search command : Author="Κοπιδάκης"  And Author="Γεώργιος"

Current Record: 9 of 19

Back to Results Previous page
Next page
Add to Basket
[Add to Basket]
Identifier 000412857
Title Theoretical investigation of tungsten disulfide-graphene heterostructures
Alternative Title Θεωρητική μελέτη ετεροδομών διθειούχου βολφραμίου -γραφενίου
Author Σταυρουλάκης, Κανάκης
Thesis advisor Κοπιδάκης, Γεώργιος
Reviewer Κιοσέογλου, Γεώργιος
Ρεμεδιάκης, Ιωάννης
Abstract Research in two-dimensional (2D) materials and van der Waals heterostructures gains enormous popularity across various scientific and engineering disciplines. Electrons in these materials can move in two dimensions but are confined in the out of plane direction, leading to some fascinating optoelectronic properties. In this direction of research, we present Density Functional Theory (DFT) results for the atomic and electronic structure of WS2 monolayer, graphene and WS2/graphene heterobilayer. We performed DFT calculations to investigate interlayer interactions and the effect of lattice mismatch in WS2/graphene van der Waals heterostructures. We found that strain affects their binding energy and electronic structure. Examining stability and band alignment in these heterostructures with DFT is quite challenging. By using different WS2/graphene supercells with different lattice mismatch and by unfolding their electronic band structure, we find that strain induces significant electronic properties modifications in the WS2 layer, such as direct to indirect band gap transitions. Furthermore, in an effort to interpret recent experiments, we studied exciton effects in WS2 monolayer using theoretical methods based on the Bethe-Salpeter equation (BSE) for 2D materials. Our excitonic spectra are in good agreement with experimental data and are affected by strain in a way which is consistent with confinement effects. Theoretical understanding of the optoelectronic properties of WS2/graphene heterostructures complements experimental works and provides a powerful tool for exploring potential applications and devices.
Language English
Issue date 2017-11-24
Collection   Faculty/Department--Faculty of Sciences and Engineering--Department of Materials Science and Technology--Post-graduate theses
  Type of Work--Post-graduate theses
Permanent Link Bookmark and Share
Views 86

Digital Documents
No preview available

View document
Views : 0