Wannier-Mott Excitons in Nanoscale Molecular Ices - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Physical Review Letters Year : 2017

Wannier-Mott Excitons in Nanoscale Molecular Ices

Y. -J. Chen
  • Function : Author
G. M. Muñoz Caro
  • Function : Author
S. Aparicio
  • Function : Author
A. Jiménez-Escobar
  • Function : Author
A. Rosu-Finsen
  • Function : Author
M. R. S. Mccoustra
  • Function : Author
A. M. Cassidy
  • Function : Author
D. Field
  • Function : Author

Abstract

The absorption of light to create Wannier-Mott excitons is a fundamental feature dictating the optical and photovoltaic properties of low band gap, high permittivity semiconductors. Such excitons, with an electron-hole separation an order of magnitude greater than lattice dimensions, are largely limited to these semiconductors but here we find evidence of Wannier-Mott exciton formation in solid carbon monoxide (CO) with a band gap of >8 eV and a low electrical permittivity. This is established through the observation that a change of a few degrees K in deposition temperature can shift the electronic absorption spectra of solid CO by several hundred wave numbers, coupled with the recent discovery that deposition of CO leads to the spontaneous formation of electric fields within the film. These so-called spontelectric fields, here approaching 4 ×107 V m-1 , are strongly temperature dependent. We find that a simple electrostatic model reproduces the observed temperature dependent spectral shifts based on the Stark effect on a hole and electron residing several nm apart, identifying the presence of Wannier-Mott excitons. The spontelectric effect in CO simultaneously explains the long-standing enigma of the sensitivity of vacuum ultraviolet spectra to the deposition temperature.
Fichier principal
Vignette du fichier
Wannier_Mott_Excitons_in_Nanoscale_Molecular_Ices.pdf (782.46 Ko) Télécharger le fichier
Origin : Publisher files allowed on an open archive

Dates and versions

insu-03749635 , version 1 (11-08-2022)

Identifiers

Cite

Y. -J. Chen, G. M. Muñoz Caro, S. Aparicio, A. Jiménez-Escobar, J. Lasne, et al.. Wannier-Mott Excitons in Nanoscale Molecular Ices. Physical Review Letters, 2017, 119, ⟨10.1103/PhysRevLett.119.157703⟩. ⟨insu-03749635⟩
25 View
23 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More