Geng Tan

Atomic step patterning in nanoimprint lithography: Molecular dynamics study

Atomic-scale formability of nanoimprint lithography using an atomically stepped mold is investigated in a molecular dynamics simulation for inorganic SiO2 glass material. Fast Fourier transformation analysis of the surface height of the glass is performed to confirm the periodicity of the atomic-step pattern. From the analysis, the resolution of glass nanoimprint lithography is found to be 0.2 nm for the atomically stepped mold. This theoretical resolution agrees with the experimental resolution.

Formation of 0.3-nm-high stepped polymer surface by thermal nanoimprinting

We performed atomic-scale surface patterning with a vertical resolution of approximately 0.3 nm on a poly(methyl methacrylate) (PMMA) polymer sheet (10 × 10 mm2) by thermal nanoimprinting using an atomically stepped sapphire template (α-Al2O3 single crystal). The sapphire mold with () r-plane exhibited regularly arranged straight steps with a uniform height of approximately 0.31 nm. The template nanopattern could be transferred onto the surface of the PMMA sheet under the imprinting conditions of 0.2 MPa load for 300 s at 140 °C. Atomic stairs with approximately 0.26-nm-high straight steps and approximately 600-nm-wide terraces were formed on the PMMA surface.

Influence of Rapid Thermal Annealing and Substrate Terrace Width on Self-Organizing Formation of Periodic Straight Nanogroove Array on NiO(111) Epitaxial Thin Film

Room-temperature-grown NiO(111) epitaxial thin films on atomically stepped sapphire (0001) substrates by pulsed laser deposition have straight atomic steps. For a terrace width of about 50 nm, a periodic straight nanogroove array with a depth of about 6 nm was formed over the film surface after rapid thermal annealing. When using a substrate with a terrace width of about 250 nm, it is observed that two types of 180°-rotated triangular crystalline domain are alternately grown on each film terrace divided by the nanogrooves.