Electrical control of neutral and charged excitons in a monolayer semiconductor
By J. Ross, Sanfeng Wu, Hongyi Yu, N. Ghimire, Aaron M. Jones, G. Aivazian, Jiaqiang Yan, D. Mandrus, Di Xiao, W. Yao and 1 more. Nature Communications, 2012
1,430 citations recorded by the source corpus.
Monolayer group-VI transition metal dichalcogenides have recently emerged as semiconducting alternatives to graphene in which the true two-dimensionality is expected to illuminate new semiconducting physics. Here we investigate excitons and trions (their singly charged counterparts), which have thus far been challenging to generate and control in the ultimate two-dimensional limit. Utilizing high-quality monolayer molybdenum diselenide, we report the unambiguous observation and electrostatic tunability of charging effects in positively charged (X+), neutral (Xo) and negatively charged (X−) excitons in field-effect transistors via photoluminescence. The trion charging energy is large (30 meV), enhanced by strong confinement and heavy effective masses, whereas the linewidth is narrow (5 meV) at temperatures <55 K. This is greater spectral contrast than in any known quasi-two-dimensional system. We also find the charging energies for X+ and X− to be nearly identical implying the same effective mass for electrons and holes. Single layers of group-VI transition metal dichalcogenides have emerged as direct bandgap semiconductors in the two-dimensional limit. The authors show that monolayer molybdenum diselenide is an ideal system enabling electrostatic tunability of charging effects in neutral and charged electron-hole pairs, so-called excitons.
Subfields: Materials Chemistry
View Paper: https://www.semanticscholar.org/paper/e265d065c74d788d155dd8fc65e788bd0604a074
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Citations in the corpus
- Emerging device applications for semiconducting two-dimensional transition metal dichalcogenides. (2014, methodology): “Adapted from ref.(56) © 2013, Macmillan Publishers Ltd.”
- Chemical vapor deposition growth of crystalline monolayer MoSe2. (2014, background): “9 eV in MoS2), a 10-fold narrower line width, and tunable excitonic charging effects.(14,15)”