Layered chalcogenide semiconductors show a wealth of exotic physical phenomena when
confined into the 2D lattice, thus providing new opportunities for electronics, optoelectronics,
and energy harvesting devices. This talk will present highlights how such emerging materials
can further benefit from electronic materials processing. I will first report how chemical doping
can drastically alter the crystal structure and optical properties of atomically-thin
chalcogenides where the electron wavefunction is tightly confined thereby strongly interacting
with the foreign atoms. I will then introduce a defect engineering method for thermal energy
applications, combined with high-energy ion irradiation that allows to modulate the density of
point defects under high controllability. This method is successfully demonstrated for highperformance
thermoelectrics by decoupling the undesired interdependence among three key
transport parameters: electrical conductivity, thermopower and thermal conductivity. It opens
an unprecedented route for enhancing energy conversion efficiency with multiple roles of
defects in narrow band gap chalcogenides.