Photoluminescence Study of B‐Trions in MoS₂ Monolayers with High Density of Defects

Abstract

Photoluminescence spectroscopy has been used to investigate the details of B band emission from single‐layer MoS2 samples grown by chemical vapor deposition. The evolution of the peak shape upon variable excitation power is well described by a combination of exciton and trion contributions, from which B trion binding energy of 18 meV has been extracted. It has been suggested that the absence of accompanying A trion emission in our samples, as well as the enhanced intensity of the B band, can be ascribed to a fast non‐radiative recombination channel arising from the large defect density in our samples. It has been found that band‐selective recombination channels or formation of dark/bright trions are possible microscopic scenarios for our observations.

MoS2 Memtransistors Fabricated by Localized Helium Ion Beam Irradiation

“…Based on our results, we propose that when switching the device into HRS, the defects on the drain-side are forced to migrate towards the drain electrode from the fissure. Their depletion from the channel attenuates B exciton intensity which is usually associated with defect concentration [29,30]. Helium ion irradiation above doses of > 1 pC µm −1 results in V S concentrations [22] induced by beam sputtering that far exceed sub-stoichiometries achieved naturally by CVD growth [31].…”

Tailoring of Bound Exciton Photoluminescence Emission in WS2 Monolayers

“…In the case of WS 2 monolayers grown by chemical vapor deposition (CVD) onto Si/SiO 2 substrates, the A and B exciton peaks are usually detected at lower energies compared with the mechanically exfoliated layers or CVD‐grown layers on other substrates . This redshift is mostly caused by the strain in the as‐grown monolayers on the Si/SiO 2 substrate . In addition to the charge‐neutral exciton peak, a charged trion peak is also often found at about 43 meV lower energies .…”

MoS2 Nanosheets with Narrowest Excitonic Line Widths Grown by Flow-Less Direct Heating of Bulk Powders: Implications for Sensing and Detection

“…Even though curve-fitting the PL to a set of Lorentzian functions is an accepted method by the majority of the TMD community, some researchers also use a combination of Lorentzian and Gaussian fitting functions. [152][153][154][155][156] This distribution does not have a closed-form solution and must be solved via numerical approaches, using the so-called "Voigt" function.…”

“…However, as lattice vibrations and defects start to perturb the exciton–phonon coupling, it adds a Gaussian component to the statistical distribution as well. Even though curve-fitting the PL to a set of Lorentzian functions is an accepted method by the majority of the TMD community, some researchers also use a combination of Lorentzian and Gaussian fitting functions. , This distribution does not have a closed-form solution and must be solved via numerical approaches, using the so-called “Voigt” function.…”