Precision synthesis

Materials synthesis is the foundation of all advanced science and engineering. 

Much of the progress in 2D materials has been enabled by micromechanical exfoliation — the original Scotch Tape method.  This is a simple and inexpensive way to generate high-quality crystals. Unfortunately, the resulting samples are small and unpredictable. 

High quality thin film growth is key to future technologies. 

Our lab is equipped with state-of-the-art synthesis facilities — some of it home-built, all of it customized — to enable detailed investigation of growth processes and produce material for advanced device fabrication. Many projects in our lab focus on developing improved methods for to grow high-quality crystals, or to control their properties via doping and polytype modification. Our work focuses on two primary synthesis techniques:

MBE involves physical vapor deposition onto atomically-clean surfaces under ultra-high vacuum (UHV, pressures typically < 10-10 mbar) from solid or gas sources with precisely calibrated fluxes. MBE is amenable to in-situ monitoring during growth (e.g., RHEED, QMS, QCM, BFM) and samples can be characterized without leaving vacuum (e.g., STM). The Mannix lab is equipped with a modern, commercial MBE chamber for growing 2D chalcogenide and pnictide materials. We are developing surface chemistry methods to enhance the quality and structural selectivity during growth of layered quantum materials in UHV.

CVD involves the deposition of vapor-phase precursors (supplied by solid, liquid, or gas sources) on a growth substrate at elevated temperatures. We use several variations of this versatile concept: