ULTRAFAST TERAHERTZ SCANNING TUNNELING MICROSCOPY OF INTERFACIAL CHARGE CARRIER DYNAMICS IN ULTRACLEAN TWO-DIMENSIONAL SEMICONDUCTOR HETEROSTRUCTURES
Abstract
Heterostructures composed of layers of two-dimensional (2D) materials such as transition metal dichalcogenides (TMDs) are capable of hosting atomically sharp interfaces both along the stacking direction (vertically) and in the plane of the monolayers (laterally). Exquisite sample cleanliness is necessary to realize the latter, as the dangling bonds at the edges of a single monolayer tend to react strongly in air. It has recently been shown that molecular beam epitaxy (MBE) can produce such heterostructures thanks to its ultrahigh purity precision growth carried out in an ultrahigh vacuum (UHV) chamber, i.e., in an ultraclean environment. Resolving the key process of charge carrier transport across such atomically sharp lateral interfaces has been elusive due to the need for a characterization technique with simultaneous atomic spatial resolution and sub-picosecond (i.e., ultrafast) temporal resolution. Yet, new possibilities have emerged with the advent of terahertz scanning tunneling microscopy (THz-STM) and the demonstration that THz-STM achieves the requisite spatio-temporal resolution in UHV. In this project, we will apply ultrafast THz-STM to ultraclean 2D semiconductor heterostructures grown by MBE to resolve charge carrier dynamics across lateral and vertical interfaces in atomic-scale detail.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 20, 2023
- Source ID
- FA95502210547
Entities
People
- Tyler L. Cocker
Organizations
- Air Force Office of Scientific Research
- Michigan State University
- United States Air Force