Formation of an Extended Quantum Dot Array Driven and Autoprotected by an Atom-Thick h-BN Layer

Abstract

Engineering quantum phenomena of two-dimensional nearly free electron states has been at the forefront of nanoscience studies ever since the first creation of a quantum corral. Common strategies to fabricate confining nanoarchitectures rely on manipulation or on applying supramolecular chemistry principles. The resulting nanostructures do not protect the engineered electronic states against external influences, hampering the potential for future applications. These restrictions could be overcome by passivating the nanostructures with a chemically inert layer. To this end we report a scalable segregation-based growth approach forming extended quasi-hexagonal nanoporous CuS networks on Cu(111) whose assembly is driven by an autoprotecting h-BN overlayer. We further demonstrate that by this architecture both the Cu(111) surface state and image potential states of the h-BN/CuS heterostructure are confined within the nanopores, effectively forming an extended array of quantum dots. Semiempirical electron-plane-wave-expansion simulations shed light on the scattering potential landscape responsible for the modulation of the electronic properties. The protective properties of the h-BN capping are tested under various conditions, representing an important step toward the realization of robust surface state based electronic devices.

Analogous electronic states in graphene and planer metallic quantum dots

“…For the degenerate n = 2 (f) and n = 3 (g) states, the intensity is depleted at the QD center where the probability density takes a donut-like form of similar wrapping as the QD shape and with progressively increasing diameter towards the QD boundaries for n = 3 state 2 . At the energy of n =4 level (h), the LDOS revealed strong intensity back at the center with additional weaker intensity contribution at the QD’s termini, thereby taking a sombrero-like shape 49 , 50 . Overall, it is clear that the full electronic band structure, particularly below 4.0 eV, and the simulated LDOS of the confined states in GQDs can be well simplified by assuming electron confinement inside homogeneous metallic QDs of the same size and shape, where here the H-MQDs offer better matching with the electronic characteristics observed in GQD.…”