相关论文: Photoluminescence kinetics of dark and bright exci…
Excitons are vital in the photophysics of materials, especially in low-dimensional systems. The conceptual and quantitative understanding of excitonic effects in nonlinear optical (NLO) processes is more challenging compared to linear ones.…
Monolayers of ReS2 were grown by a chemical vapor deposition technique on SiO2/Si substrates and investigated at room temperature by using micro-Raman, micro-photoluminescence (PL) and absorbance spectroscopies. The Raman scattering…
Transition metal dichalcogenides (TMDs) are layered materials that have a semiconducting phase with many advantageous optoelectronic properties, including tightly bound excitons and spin-valley locking. In Tungsten-based TMDs, spin and…
The spectral and spatiotemporal dynamics of photoluminescence in monolayers of transition metal dichalcogenide WSe$_2$ obtained by mechanical exfoliation on a Si/SiO$_2$ substrate is studied over a wide range of temperatures and excitation…
We report on polarization-resolved resonant photoluminescence (PL) spectroscopy of bright (spin-1) and dark (spin-2) excitons in colloidal CdSe nanocrystal quantum dots. Using high magnetic fields to 33 T, we resonantly excite (and…
The optical spectra of vertically stacked MoSe$_2$/WSe$_2$ heterostructures contain additional 'interlayer' excitonic peaks that are absent in the individual monolayer materials and exhibit a significant spatial charge separation in…
We present low temperature magneto-photoluminescence experiments which demonstrate the brightening of dark excitons by an in-plane magnetic field $B$ applied to monolayers of different semiconducting transition metal dichalcogenides. For…
The band structure of MoS$_2$ strongly depends on the number of layers, and a transition from indirect to direct-gap semiconductor has been observed recently for a single layer of MoS$_2$. Single-layer MoS$_2$ therefore becomes an efficient…
We study photoluminescence (PL) spectra and exciton dynamics of MoS$_2$ monolayer (ML) grown by the chemical vapor deposition technique. In addition to the usual direct A-exciton line we observe a low-energy line of bound excitons…
We investigate exciton confinement to a quantum wire in monolayer $\text{MoSe}_2$ where the confinement is achieved by a p-i-n junction. We employ an effective-mass exciton model and solve the problem numerically, reflecting device…
Atomically thin semiconductors such as monolayer MoS2 and WS2 exhibit nonlinear exciton-exciton annihilation at notably low excitation densities (below ~10 excitons/um2 in MoS2). Here, we show that the density threshold at which…
Coulomb bound electron-hole pairs, excitons, govern the optical properties of semi-conducting transition metal dichalcogenides like MoS$_2$ and WSe$_2$. We study optical transitions at the K-point for 2H homobilayer MoS$_2$ in Density…
Here, we show that deep trapped "dark" exciton states are responsible for the surprisingly long lifetime of band-edge photoluminescence in acid-treated single-layer MoS2. Temperature-dependent transient photoluminescence spectroscopy…
Temperature influences the performance of two-dimensional materials in optoelectronic devices. Indeed, the optical characterization of these materials is usually realized at room temperature. Nevertheless most {\it ab-initio} studies are…
Excitons in MoS2 dominate the absorption and emission properties of the two-dimensional system. Here, we study the microscopic origin of the electroluminescence from monolayer MoS2 fabricated on a heavily p-type doped silicon substrate. By…
Transition metal dichalcogenides hold promise for applications in novel optoelectronic devices. There is therefore a need for materials that can be obtained in large quantities and with well understood optical properties. In this report, we…
In semiconductor physics, many essential optoelectronic material parameters can be experimentally revealed via optical spectroscopy in sufficiently large magnetic fields. For monolayer transition-metal dichalcogenide semiconductors, this…
We discuss the linear and two-photon spectroscopic selection rules for spin-singlet excitons in monolayer transition-metal dichalcogenides. Our microscopic formalism combines a fully $k$-dependent few-orbital band structure with a many-body…
Structural defects in 2D-transition metal dichalcogenides are critical in modulating their optical and electrical behavior. Nevertheless, precise defect control within the monolayer regime poses a significant challenge. Herein, a…
We investigate electrical gating of photoluminescence and optical absorption in monolayer molybdenum disulfide (MoS$_2$) configured in field effect transistor geometry. We observe an hundredfold increase in photoluminescence intensity and…