2017/03/31 by Garima Gupta, Sangeeth Kallatt, Kausik Majumdar · 2 citations
Biochemistry, Genetics and Molecular Biology · Materials Science · Physics and Astronomy · #2D Materials and Applications #Advanced biosensing and bioanalysis techniques #Atomic physics #Band gap #Binding energy #Condensed matter physics #Dielectric #Exciton #Materials science #Monolayer #Nanotechnology #Optoelectronics #Photoluminescence #Physics #Quantum Dots Synthesis And Properties #Quantum mechanics #Renormalization #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.96.081403
published as Phys. Rev. B 96, 081403 (2017) · 19 pages including supplemental information
openalex created_date 2017/04/28 · openalex publication_date 2017/08/07 · arxiv created 2017/08/15 · arxiv updated 2017/08/16 · openalex updated_date 2026/08/05
Screening due to the surrounding dielectric medium reshapes the electron-hole interaction potential and plays a pivotal role in deciding the binding energies of strongly bound exciton complexes in quantum confined monolayers of transition metal dichalcogenides (TMDs). However, owing to strong quasiparticle band-gap renormalization in such systems, a direct quantification of estimated shifts in binding energy in different dielectric media remains elusive using optical studies. In this work, by changing the dielectric environment, we show a conspicuous photoluminescence peak shift at low temperature for higher energy excitons (2s,3s,4s,5s) in monolayer MoSe2, while the 1s exciton peak position remains unaltered -- a direct evidence of varying compensation between screening induced exciton binding energy modulation and quasiparticle band-gap renormalization. The estimated modulation of binding energy for the 1s exciton is found to be 58.6% (72.8% for 2s,75.85% for 3s, and 85.6% for 4s) by coating an Al2O3 layer on top, while the corresponding reduction in quasiparticle band-gap is estimated to be 246 meV. Such direct evidence of large tunability of the binding energy of exciton complexes as well as the band-gap in monolayer TMDs holds promise of novel device applications.