Coherent imaging and dynamics of excitons in MoSe monolayers epitaxially grown on hexagonal boron nitride.

Using four-wave mixing microscopy, we measure the coherent response and ultrafast dynamics of excitons and trions in MoSe monolayers grown by molecular beam epitaxy on thin films of hexagonal boron nitride. We assess inhomogeneous and homogeneous broadenings in the transition spectral lineshape. The impact of phonons on the homogeneous dephasing is inferred the temperature dependence of the dephasing.

Narrow Excitonic Lines and Large-Scale Homogeneity of Transition-Metal Dichalcogenide Monolayers Grown by Molecular Beam Epitaxy on Hexagonal Boron Nitride.

Monolayer transition-metal dichalcogenides (TMDs) manifest exceptional optical properties related to narrow excitonic resonances. However, these properties have been so far explored only for structures produced by techniques inducing considerable large-scale inhomogeneity. In contrast, techniques which are essentially free from this disadvantage, such as molecular beam epitaxy (MBE), have to date yielded only structures characterized by considerable spectral broadening, which hinders most of the interesting optical effects.

Polarization and magneto-optical properties of excitonic emission from wurtzite CdTe/(Cd,Mg)Te core/shell nanowires.

Wurtzite CdTe and (Cd,Mn)Te nanowires embedded in (Cd,Mg)Te shells are grown by employing vapour-liquid-solid growth mechanism in a system for molecular beam epitaxy. A combined study involving cathodoluminescence, transmission electron microscopy and micro-photoluminescence is used to correlate optical and structural properties in these structures. Typical features of excitonic emission from individual wurtzite nanowires are highlighted including the emission energy of 1.