Ultrafast carrier dynamics of Bi2O2Se nanoplates in the nonlinear excitation regime

Excimer Formation in the Non‐Van‐Der‐Waals 2D Semiconductor Bi2O2Se

“…The Raman spectrum of Bi 2 O 2 Se nanosheets is shown in Figure S2 (Supporting Information), which is dominated by a fully symmetrical A 1g phonon mode at 159 cm −1 with a super narrow full width at half maximum (≈4 cm −1 ), indicating that grown Bi 2 O 2 Se nanosheets can be considered as perfect crystals and defects related carrier trapping process can be ruled out. [ 21 ] Additional characterizations of the Bi 2 O 2 Se nanosheet to confirm the high crystal quality are presented in Figure S3 (Supporting Information). Before investigating the photoexcited carrier dynamics, we have first checked optical transitions in the 18‐layer Bi 2 O 2 Se nanosheet.…”

A hidden phase uncovered by ultrafast carrier dynamics in thin Bi2O2Se

“…26 Moreover, the independence of phonon width from film thickness indicates consistent film quality across different thicknesses, ruling out any defects associated with carrier trapping processes. 23 Furthermore, the effective e–ph coupling strength is extracted from the integrated intensity, following the method described in ref. 27.…”

“…22 Han et al attributed both the fast (∼8 ps) and slow (∼90 ps) lifetimes to the phonon-assisted carrier relaxation processes in a CVD-grown 27.5 nm-thick sample. 23 With various timescales observed in different thicknesses, direct comparisons become challenging. It is, therefore, imperative to systematically investigate thickness-dependent ultrafast carrier dynamics.…”

Insights into electron dynamics in two-dimensional bismuth oxyselenide: a monolayer-bilayer perspective

“…[9][10][11][12][13][14][15][16] A noteworthy commonality among these materials is the presence of a van der Waals (vdW) gap in their respective three-dimensional (3D) parent structures. 17 In contrast to vdW laminates, Bi 2 O 2 Se emerges as a prototypical bismuth-based oxygen-sulfur semiconductor, comprising Bi 2 O 2 layers and Se layers held together by weak electrostatic forces, [18][19][20][21][22][23] imparting distinctive properties to the material. 2D semiconductors characterized by flat surfaces devoid of defect states or dangling bonds, exhibit the potential to mitigate scattering from uneven surfaces and enhance carrier mobility.…”