WSe2 light-emitting tunneling transistors with enhanced brightness at room temperature
| Autor: | S. Schwarz, Colin R. Woods, Andre K. Geim, T. Taniguchi, Peter Blake, S. Dufferwiel, T. Godde, Freddie Withers, Sarah J. Haigh, Kenji Watanabe, Vladimir I. Fal'ko, Alexander I. Tartakovskii, O. Del Pozo-Zamudio, Igor L. Aleiner, A. P. Rooney, Paul M. Walker, Ali Gholinia, K. S. Novoselov |
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| Rok vydání: | 2015 |
| Předmět: |
Photoluminescence
Materials science Condensed Matter - Mesoscale and Nanoscale Physics Graphene business.industry Mechanical Engineering FOS: Physical sciences Bioengineering Nanotechnology General Chemistry Condensed Matter Physics law.invention chemistry.chemical_compound Semiconductor chemistry law Mesoscale and Nanoscale Physics (cond-mat.mes-hall) Optoelectronics Tungsten diselenide General Materials Science Direct and indirect band gaps Quantum efficiency business Quantum well Quantum tunnelling |
| ISSN: | 1530-6984 |
| DOI: | 10.48550/arxiv.1511.06265 |
| Popis: | Monolayers of molybdenum and tungsten dichalcogenides are direct bandgap semiconductors, which makes them promising for opto-electronic applications. In particular, van der Waals heterostructures consisting of monolayers of MoS2 sandwiched between atomically thin hexagonal boron nitride (hBN) and graphene electrodes allows one to obtain light emitting quantum wells (LEQWs) with low-temperature external quantum efficiency (EQE) of 1%. However, the EQE of MoS2 and MoSe2-based LEQWs shows behavior common for many other materials: it decreases fast from cryogenic conditions to room temperature, undermining their practical applications. Here we compare MoSe2 and WSe2 LEQWs. We show that the EQE of WSe2 devices grows with temperature, with room temperature EQE reaching 5%, which is 250x more than the previous best performance of MoS2 and MoSe2 quantum wells in ambient conditions. We attribute such a different temperature dependences to the inverted sign of spin-orbit splitting of conduction band states in tungsten and molybdenum dichalcogenides, which makes the lowest-energy exciton in WSe2 dark. |
| Databáze: | OpenAIRE |
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