3 research outputs found
A Direct Sensor to Measure Minute Liquid Flow Rates
Nanofluidics
finds its root in the study of fluids and flows at
the nanoscale. Flow rate is a quantity that is both central when dealing
with flows and notoriously difficult to measure experimentally at
the scale of an individual nanopore or nanochannel. We show in this
letter that minute flow rate can be directly measured accumulating
liquid over time within the compliant membrane of a commercial piezoresistive
pressure sensor. Our flow rate sensor is versatile and can be operated
independently of the nature of the liquid, flow profile, and type
of nanochannel. We demonstrate this method by measuring the pressure-driven
flow of silicon oil in a single nanochannel of average radius 200
nm. This approach gives reliable measurement of the flow rate up to
1 pL/min. Unlike other nanoscale flow measurements methods based,
for instance, on particle tracking, our sensor delivers a direct voltage
output suitable for nanoflow control applications
Fabrication of Buckling Free Ultrathin Silicon Membranes by Direct Bonding with Thermal Difference
An innovative method to fabricate large area (up to several squared millimeters) ultrathin (100 nm) monocrystalline silicon (Si) membranes is described. This process is based on the direct bonding of a silicon-on-insulator wafer with a preperforated silicon wafer. The stress generated by the thermal difference applied during the bonding process is exploited to produce buckling free silicon nanomembranes of large areas. The thermal differences required to achieve these membranes (≥1 mm<sup>2</sup>) are estimated by analytical calculations. An experimental study of the stress achievable by direct bonding through two specific surface preparations (hydrophobic or hydrophilic) is reported. Buckling free silicon nanomembranes secured on a 2 × 2 cm<sup>2</sup> frame with lateral dimensions up to 5 × 5 mm<sup>2</sup> are successfully fabricated using the optimized direct bonding process. The stress estimated by theoretical analysis is confirmed by Raman measurements, while the flatness of the nanomembranes is demonstrated by optical interferometry. The successful fabrications of high resolution (50 nm half pitch) tungsten gratings on the silicon nanomembranes and of focused ion beam milling nanostructures show the promising potential of the Si membranes for X-ray optics and for the emerging nanosensor market
Supplementary document for Single SiGe Quantum Dot Emission Deterministically Enhanced in a High-Q Photonic Crystal Resonator - 6176570.pdf
Additional Information to the main paper