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A resonator system has been fabricated directly on a pre-processed CMOS chip. The system is to be used for high sensitivity mass sensing applications in air and vacuum. The resonator system, corresponding of a cantilever and structures for electrostatic actuation and capacitive read-out, have been defined by electron beam lithography on top of a charge and radiation sensitive CMOS layer in predefined areas as a post-process step. This has been accomplished without affecting the electronic properties of the pre-processed CMOS circuits. The subsequent etching steps to fully release the cantilevers have been obtained without stiction of the cantilevers to the substrate. Cantilevers are driven at their mechanical resonance in a lateral mode, and the frequency is monitored by capacitive read-out on the chip. CMOS integration enables signal detection directly on the chip, which radically decreases the parasitic capacitances. Consequently, low-noise electrical measurements with a very high mass sensitivity are obtained. Fabricated resonator systems were characterized to have resonance frequencies of approximately 1.49 MHz, which is in good agreement with a theoretical estimation of 1.41 MHz. The theoretical mass resolution, [inline image], is approximately 17 ag Hz-1, using a Young modulus value of 160 GPa. [ABSTRACT FROM AUTHOR]

Nanoimprint lithography (NIL) is a nonconventional lithographic technique that promises low-cost, high-throughput patterning of structures with sub-10 nm resolution. Contamination of nanoimprint stamps is one of the key obstacles to industrialize the NIL technology. Here, we report two efficient approaches for removal of typical contamination of particles and residual resist from stamps: thermal and ultraviolet (UV) imprinting cleaning-both based on the self-cleaning effect of imprinting process. The contaminated stamps were imprinted onto polymer substrates and after demolding, they were treated with an organic solvent. The images of the stamp before and after the cleaning processes show that the two cleaning approaches can effectively remove contamination from stamps without destroying the stamp structures. The contact angles of the stamp before and after the cleaning processes indicate that the cleaning methods do not significantly degrade the anti-sticking layer. The cleaning processes reported in this work could also be used for substrate cleaning.

We present a novel scheme for producing nanotube membranes using free-standing hollow nanowires, with easily controllable dimensions. GaAs-AlInP core-shell nanowires were grown by metal-organic vapor phase epitaxy and were partially embedded in a polymer film. The GaAs core and substrate were etched selectively, leaving tubes with open access to both sides of the membrane. Electrophoretic transport of T4-phage DNA through the hollow nanowires was demonstrated using epifluorescence microscopy.

We demonstrate high-fidelity guidance of axons using rows of nanowires. The axons are prevented from crossing the rows, making it possible to guide and sort a large number of axons as opposed to when chemical patterns are used. Focal adhesion forms at the nanowires establishing a possible site of information transfer between the surface and the cells. Rows of gallium phosphide (GaP) nanowires were epitaxially grown on GaP(111) substrates in patterns defined by electron beam lithography.