Thermalization of photoexcited localized excitons in GaSe samples with stacking disorder

Two-Dimensional Metal–Chalcogenide Films in Tunable Optical Microcavities

“…In the case of the half-cavity configuration, a clear sublinear PL intensity growth with power is seen. PL saturation is observed at around P = 10 mW, indicating that the optical pumping rate exceeds the relatively low recombination rate 1/τ hc (τ hc ≈ 700 ps) of the localized exciton states in GaSe. , In contrast to this, a much stronger PL increase with power is found for the cavity mode in the full-cavity configuration. No PL saturation is observed, indicating that the spontaneous recombination rate remains higher than the excitation rate in the whole range of powers used.…”

“…The PL line width for both materials is determined by inhomogeneous broadening caused by variations of the exciton potential within the film area illuminated by the laser. In Figure a PL from a MoS 2 monolayer is observed in a wide range from 640 to 740 nm (1.67–1.94 eV). , Figure b shows PL for a 43 nm thick GaSe film with a spectrum in the range 600–625 nm (1.98–2.07 eV) corresponding to the emission from localized exciton states, probably occurring due to the interlayer stacking defects …”

“… 9 , 29 Figure 2 b shows PL for a 43 nm thick GaSe film with a spectrum in the range 600–625 nm (1.98–2.07 eV) corresponding to the emission from localized exciton states, probably occurring due to the interlayer stacking defects. 30 …”

“…9,28 Figure 2b shows PL for a 43 nm thick GaSe film with a spectrum in the range 600−625 nm (1.98−2.07 eV) corresponding to the emission from localized exciton states, probably occurring due to the interlayer stacking defects. 29 The cavity is formed by moving the top mirror above the optically excited area of the film, with the laser coupled through the top DBR (the "full-cavity" configuration). In this configuration the PL is coupled into cavity modes having typical Q-factors of a few 10 3 and for some mirrors reaching up to 7400 (Supporting Information).…”

Layered III-VI chalcogenide semiconductor crystals for radiation detectors

“…The most intense GaSe peak at around 2.093 eV is an acceptor bound exciton, and the highest energy peak is related to a free exciton emission around 2.114 eV. 22 The free excitonic peak position for GaSe was reported by Taylor and Ryan 23 at 2.106 eV. The peak at 2.065 eV is related to impurities and is yet to be assigned.…”