An array of very uniform cylindrical nanopores with a pore diameter as small as 25 nm has been fabricated in an ultrathin micromachined silicon nitride membrane using focused ion beam (FIB) etching. The pore size of this nanosieve membrane was further reduced to below 10 nm by coating it with another silicon nitride layer. This nanosieve membrane possesses adequate mechanical strength up to several bars of transmembrane pressure, and it can withstand high temperatures up to 900 °C. In addition, it is inert to many aggressive chemicals such as hot concentrated potassium hydroxide (KOH), piranha (H 2 SO 4 + H 2 O 2 ), and nitric acid (HNO 3 ).

Palladium nanowires were fabricated on silicon substrates using conventional microfabrication techniques. Sensors based on such nanowires show a reversible response to hydrogen concentrations as low as 27 ppm with response times varying from 5 s (H2 concentrations >20%) to 30 s (H2 concentrations <100 ppm) at room temperature. The response times can be reduced by increasing the applied bias due to resistive heating. The noise spectrum of the nanowires shows a 1/f behavior, sufficiently low to enables the detection of hydrogen with an ultralow-power consumption. The influence of oxygen on the nanowire response was also investigated.

Arrays of small nanomechanical resonators with dual geometry have been fabricated for sensitive biological detection. The arrays consist of silicon nitride resonating 100 nm thick cantilevers with sensing gold areas alternately placed on the free and fixed cantilever ends. The Au areas act as sensing regions as can be functionalized by means of thiol chemistry. The nanomechanical arrays provide a double flavor of the adsorbed molecules: the added mass reported by the cantilevers with the Au area at the tip and the nanoscale elasticity reported by the cantilevers with the Au area at the clamp. The devices were applied for DNA detection based on Watson-Crick pairing rules. The proposed design for nanomechanical resonators provides higher specificity for DNA sensing in comparison with conventional single cantilevers. The nanoscale elasticity induced by the DNA hybridization arises from the intermolecular interactions between the adsorbates bound to the cantilever and the surface stress.

A new low-cost, top-down nanowire fabrication technology is presented not requiring nanolithography and suitable for any conventional microtechnology cleanroom facility. This novel wafer-scale process technology uses a combination of angled thin-film deposition and etching of a metal layer in a precisely defined cavity with a single micrometer-scale photolithography step. Electrically functional silicon and metallic nanowires with lengths up to several millimeters, lateral widths of 100 nm, and thicknesses 20 nm have been realized and tested. Device characterization includes a general description of device operation, electrochemical biasing, and sensitivity for sensor applications followed by electrical measurements showing linear i-v characteristics with specific contact resistivity rhoc approximately 4 x 10-4 ohm's cm2 and electrochemical behavior of the oxidized silicon nanowires is described with the site-binding model.

A self-seeding microwell chip is introduced for the isolation and interrogation of single cells. A cell suspension is transferred to a microwell chip containing 6400 microwells, each microwell with a single 5 μm pore in the bottom. The fluid enters the microwell and drags a cell onto the pore. After a cell has landed onto the pore, it will stop the fluid flow through this microwell. The remaining fluid and cells will be diverted to the next available microwell. This results in a fast and efficient distribution of single cells in individual microwells. After identification by fluorescence microscopy, the cells of interest are isolated from the microwell by punching the bottom together with the cell. The overall single cell recovery of seeding followed by isolation of the single cell, is >70% with a specificity of 100% as confirmed by the genetic make-up of the isolated cells.

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In the present work, we investigate systematically the electronic and optical properties of Janus ZrSSe using first-principles calculations. Our calculations demonstrate that the Janus ZrSSe monolayer is an indirect semiconductor at equilibrium. The band gap of the Janus ZrSSe is 1.341 eV using the Heyd-Scuseria-Ernzerhof hybrid functional, larger than the band gap of ZrSe 2 monolayer and smaller than that of ZrS 2 monolayer. Based on the analysis of the band edge alignment, we confirm that the Janus ZrSSe monolayer possesses photocatalytic activities that can be used in water splitting applications.While strain engineering plays an important role in modulating the electronic properties and optical characteristics of the Janus ZrSSe monolayer, the influence of the external electric field on these properties is negligible. The biaxial strain, 3 b , has significantly changed the band of the Janus ZrSSe monolayer, and particularly, the semiconductor-metal phase transition which occurred at 3 b ¼ 7%. The Janus ZrSSe monolayer can absorb light in both visible and ultraviolet regions. Also, the biaxial strain has shifted the first optical gap of the Janus ZrSSe monolayer. Our findings provide additional information for the prospect of applying the Janus ZrSSe monolayer in nanoelectronic devices, especially in water splitting technology.

In this paper, detailed investigations of the electronic and optical properties of a Janus SnSSe monolayer under a biaxial strain and electric field using ab initio methods are presented.