Efficient Charge Separation in 2D Janus van der Waals Structures with Built-in Electric Fields and Intrinsic p–n Doping
| Autor: | Mohnish Pandey, Kristian Sommer Thygesen, Anders C. Riis-Jensen |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Exciton FOS: Physical sciences 02 engineering and technology Electron 01 natural sciences Condensed Matter::Materials Science symbols.namesake Electric field 0103 physical sciences Surface charge Physical and Theoretical Chemistry 010306 general physics Electronic band structure Condensed Matter - Materials Science Condensed matter physics Materials Science (cond-mat.mtrl-sci) 021001 nanoscience & nanotechnology Surfaces Coatings and Films Electronic Optical and Magnetic Materials Dipole General Energy symbols Vacuum level van der Waals force 0210 nano-technology |
| Zdroj: | Riis-Jensen, A C, Pandey, M & Thygesen, K S 2018, ' Efficient Charge Separation in 2D Janus van der Waals Structures with Built-in Electric Fields and Intrinsic p-n Doping ', Journal of Physical Chemistry C, vol. 122, no. 43, pp. 24520-24526 . https://doi.org/10.1021/acs.jpcc.8b05792 The Journal of Physical Chemistry C |
| ISSN: | 1932-7455 1932-7447 |
| Popis: | Janus MoSSe monolayers were recently synthesised by replacing S by Se on one side of MoS$_2$ (or vice versa for MoSe$_2$). Due to the different electronegativity of S and Se these structures carry a finite out-of-plane dipole moment. As we show here by means of density functional theory (DFT) calculations, this intrinsic dipole leads to the formation of built-in electric fields when the monolayers are stacked to form $N$-layer structures. For sufficiently thin structures ($N4$. Based on band structure calculations and the Mott-Wannier exciton model, we compute the energies of intra- and interlayer excitons as a function of film thickness suggesting that the Janus multilayer films are ideally suited for achieving ultrafast charge separation over atomic length scales without chemical doping or applied electric fields. Finally, we explore a number of other potentially synthesisable 2D Janus structures with different band gaps and internal dipole moments. Our results open new opportunities for ultrathin opto-electronic components such as tunnel diodes, photo-detectors, or solar cells. |
| Databáze: | OpenAIRE |
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