Defect states in magnetically "seasoned" WSSe - adsorption and doping effects of magnetic transition metals X = V, Cr, Mn, Fe, Co - a comprehensive first-principles study.

Besides the symmetry breaking of Janus transition metal dichalcogenides (TMDs), Janus-based Diluted Magnetic Semiconductors (DMS) are attractive to study considering the local symmetry of transition metal (TM) dopant/adatom. This study conducts a first-principles calculation of magnetic properties in TM (V, Cr, Mn, Fe, and Co) -- doped and adsorbed Janus WSSe. Our results reveal that TM's atomic/ionic size impacts d-p-d orbital overlap, affecting bond length/angle and defect state positions.

Linearly polarized photoluminescence of InGaN quantum disks embedded in GaN nanorods.

We have investigated the emission from InGaN/GaN quantum disks grown on the tip of GaN nanorods. The emission at 3.21 eV from the InGaN quantum disk doesn't show a Stark shift, and it is linearly polarized when excited perpendicular to the growth direction.

Temperature induced crossing in the optical bandgap of mono and bilayer MoS on SiO.

Photoluminescence measurements in mono- and bilayer-MoS on SiO were undertaken to determine the thermal effect of the MoS/SiO interface on the optical bandgap. The energy and intensity of the photoluminescence from monolayer MoS were lower and weaker than those from bilayer MoS at low temperatures, whilst the opposite was true at high temperatures above 200 K. Density functional theory calculations suggest that the observed optical bandgap crossover is caused by a weaker substrate coupling to the bilayer than to the monolayer.

Interplay between many body effects and Coulomb screening in the optical bandgap of atomically thin MoS.

Due to its unique layer-number dependent electronic band structure and strong excitonic features, atomically thin MoS is an ideal 2D system where intriguing photoexcited-carrier-induced phenomena can be detected in excitonic luminescence. We perform micro-photoluminescence (PL) measurements and observe that the PL peak redshifts nonlinearly in mono- and bi-layer MoS as the excitation power is increased. The excited carrier-induced optical bandgap shrinkage is found to be proportional to n, where n is the optically-induced free carrier density.