Transition metal dichalcogenides (TMDs, MX2 with M = Mo, W and X = S, Se) are a new class of two-dimensional (2D) semiconductors. We fabricate atomically thin samples, create heterostructures and devices, and employ optical and electrical probes to study their unique properties. Recent topics of interests include valley- and spin-dependent transport, exciton condensation, and strong correlation physics of moire flat bands.
