The interplay between excitons and trions in a monolayer of MoSe2

Abstract

We study the impact of a free carrier reservoir on the optical properties of excitonic and trionic complexes in a MoSe 2 monolayer at cryogenic temperatures. By applying photodoping via a non-resonant pump laser the electron density can be controlled in our sample and in turn the exciton and trion densities can be tuned. We find a significant increase of the trion binding energy in the presence of an induced electron gas both in power-and in time-resolved photoluminescence spectra. This behaviour is reproduced within the original variational approach that takes into account both screening and phase space filling effects.

Homogeneity and tolerance to heat of monolayer MoS2 on SiO2 and h-BN

“…The exciting light was focused on the samples with a diameter (full width at half maximum: FWHM) of approximately 0.65 mm using a 100Â objective lens, and the total laser power on the samples was xed below 300 mW to prevent local heating or the deterioration of sample MoS 2 by laser illumination. 9,22,23 The Si Raman peak at 520.7 cm À1 was used as an internal reference to calibrate the Raman peaks of MoS 2 . In preliminary experiments, we monitored the PL and Raman spectra from an arbitrary point on monolayer MoS 2 for 2 hours under our experimental conditions, with no meaningful changes observed.…”

Integration of atomically thin layers of transition metal dichalcogenides into high-Q, monolithic Bragg-cavities: an experimental platform for the enhancement of the optical interaction in 2D-materials

“…al. [62]. The prominent splitting in two peaks at cryogenic conditions indicates, that both excitonic and trionic oscillations are essentially unaffected by the application of the SiO 2 coating.…”

Controllable Magnetic Proximity Effect and Charge Transfer in 2D Semiconductor and Double‐Layered Perovskite Manganese Oxide van der Waals Heterostructure

“…The cleaved surface of Mn oxide was exhibited by atomic force microscopy (AFM) (Figure 1c), indicating that the double-layered Mn oxide has an atomically flat surface morphology with a root-mean-square (RMS) roughness of only 0.2 nm, which enables good contact with the atomically thinlayered MoSe 2 and h-BN. Figure 2a shows contour maps of the temperature-dependent PL spectra of 1L-MoSe 2 /h-BN as a reference (left) and vdW heterostructure of 1L-MoSe 2 /Mn oxide (right), respectively, from 10 to 300 K. The two prominent PL peaks of the neutral excitons (X) and trions (T) are observed at a low temperature below 80 K [29][30][31][32] in both maps, while the PL intensities of trions drop significantly above 60 K with increasing temperature. [29] The PL peaks of the excitons in both maps gradually shift to the lower energy side because of the shrinkage of the bandgap of 1L-MoSe 2 , which occurs due to thermal lattice expansions.…”