Multi-Dimensional Control in Laterally-Confined Atomically-Thin Nanostructures

Reduced dimensionality has long been exploited in semiconductor nanostructures to advance fundamental discoveries and size-tunable opto-electronic technologies. In two-dimensional (2D) semiconductors, inversion asymmetry can give rise to exotic emergent degrees of freedom. Although these properties are analogous to traditional electron spin, with potential applications in quantum information processing, deliberate control of these pseudo-spins is not yet robust. The objective of this research is to harness lateral quantum confinement in monolayer materials to provide a new handle for manipulating excitations in 2D semiconductor nanostructures, thereby enabling multi-dimensional control of designed material properties. The technical approach explored in this research is to apply state-of-the-art top-down semiconductor processing techniques to pattern lateral confinement and to deliberately manipulate excitons and pseudo-spins in semiconductor nanostructures made from monolayer transition metal dichalcogenides and their heterostructures. Control of confinement will be exploited (i) to demonstrate size-tunable control of dynamics of 2D excitations, (ii) to isolate single quantum excitations that preserve the symmetry of the 2D band, and (iii) to demonstrate novel schemes for multidimensional manipulation of excitations simultaneously leveraging multiple distinct interactions. If successful, this research will result in a new class of size-tunable monolayer material platform with multiple intrinsic quantum degrees of freedom that can be deliberately engineered at the atomic size scale. This research will impact the development of diverse and adaptable nano-scale material platforms for integration into opto-electronic devices useful for classical and quantum logic. Specifically, engineering of confinement in monolayer semiconductor nanostructures will enable development of logic circuits that exploit intrinsic crystal symmetries for atomic-scale devices with tailored quantum properties.