Dielectric Constant in Nanoscale Bubbles on MoS2

Dielectric Constant of a Single MoO3 Nanostructure

MoO3 is a promising transition metal oxide due to its high dielectric constant (κ) and multifunctionality in electronic and optoelectronic applications. Oxidation-induced nanoscale MoO3, synthesized via oxidation scanning probe lithography (o-SPL) of MoS2, requires in-depth characterization of its dielectric properties. In this study, we measured the κ of a single MoO3 nanostructure, which was confirmed to be in the amorphous phase through water solubility tests and high-resolution transmission electron microscopy (HRTEM). Using electrostatic force microscopy (EFM) and numerical calculations, we determined a high κ value of approximately 25, nearly six times higher than that of SiO2. Additionally, nanoscale κ imaging revealed that the κ of MoO3 nanostructures is independent of their size. These findings suggest that oxidation-induced MoO3 nanostructures are promising candidates as high-κ dielectric materials for future nanoscale devices.

Mechanical Mapping of Nanoblisters Confined by Two-Dimensional Materials Reveals Complex Ridge Patterns

Understanding the mechanics of blisters confined by two-dimensional (2D) materials is of great importance for either fundamental studies or for their practical applications. In this work, we investigate the mechanical properties of nanoscale 2D material blisters using contact-resonance atomic force microscopy (CR-AFM). From the measurement results at the blister centers, the blisters' internal pressures are characterized, which are shown to be inversely proportional to the blisters' sizes. Our measurements agree considerably well with values predicted by theoretical mechanic analyses of the blisters. In addition, high-resolution mechanical mapping with CR-AFM reveals fine, complex ridge patterns of the blisters' confining membranes, which can hardly be distinguished from their topographies. The pattern complexity of a blister system is shown to increase with an increase in its bendability.