Our lab studies quantum transport in mesoscopic devices. We are particularly interested in topological phases of matter, quantum phase transitions, and spintronic properties in mesoscopic van-der-Waals materials including graphene and layered chalcogenides. Van-der-Waals materials are easily processible into low-dimensional structures by mechanical exfoliation, and are expected to have many novel quantum properties, which remain poorly understood. Most recently nanostructured chalcogenides have attracted substantial interests because of the newly discovered topological phases of matter; i.e., phases characterized by topological invariants rather than broken symmetries. To create novel nanostructures from van der Waals materials, we employ state-of-the-art nano-fabrication techniques including vertical stacking of atomic layers into heterostructures in a chosen sequence. Our ultimate goals are to understand quantum-mechanical effects in low-dimensional devices and eventually to create novel quantum devices.