Determination of the In-Plane Exciton Radius in 2D CdSe Nanoplatelets via Magneto-Optical Spectroscopy
Colloidal, two-dimensional semiconductor nanoplatelets (NPLs) present a unique electronic structure that arises from quantum confinement in only one dimension. While it is often assumed that the lack of quantum confinement in the lateral plane yields a spatially extended exciton, reduced dielectric screening potentially challenges this picture. Here, we implement absorption spectroscopy in pulsed magnetic fields up to 60 T for three different CdSe NPL thicknesses and lateral areas. Based on diamagnetic shifts, we find that exciton lateral extent is comparable to NPL thickness, indicating that the quantum confinement and reduced screening concomitant with few-monolayer thickness strongly reduces the exciton lateral extent. Atomistic electronic structure calculations of the exciton size for varying lengths, widths, and thicknesses support the substantially smaller in-plane exciton extent.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- 89233218CNA000001; AC02-06CH11357
- OSTI ID:
- 1544703
- Alternate ID(s):
- OSTI ID: 1570238
- Report Number(s):
- LA-UR-19-23578
- Journal Information:
- ACS Nano, Vol. 13, Issue 8; ISSN 1936-0851
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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