Capillary-Driven Flow in Triangular Nanofluidic Channel Fabricated via Nanoimprint Lithography with Heterogeneous Semiconductor Materials

In this study, hollow single- and triple-layer triangular nanofluidic channels with heterogeneous semiconductor walls composed of gallium nitride (GaN) and silicon nitride (Si₃N₄) were fabricated via nanoimprint lithography and PECVD-based thin-film deposition to investigate capillary-driven flow behaviors of liquids commonly used in biological applications. The fabricated single-layer channels enabled quantitative characterization of capillary-driven flow transport, while the triple-layer channels demonstrated the feasibility of extending the fabrication strategy to multilayer nanofluidic architectures.

The measured flow velocities inside single-layer nanofluidic channels for the test liquids ranged from 0.17 to 16.86 μm/s. Based on the experimentally measured flow velocities, the calculated capillary pressures, pressure drops, and average wall shear stresses were 0.46–1.27 MPa, 27–113 Pa, and 1.32–3.65 kPa, respectively. The results demonstrated that liquid viscosity and surface wettability would influence capillary-driven flow transport, providing quantitative insights into passive capillary flow in nanofluidic channels and establishing a foundation for the design of future biomedical and analytical nanofluidic devices.