Implementing the Reactor Geometry in the Modeling of Chemical Bath Deposition of ZnO Nanowires.

The formation of nanowires by chemical bath deposition is of great interest for a wide variety of optoelectronic, piezoelectric, and sensing devices, from which the theoretical description of their elongation process has emerged as a critical issue. Despite its strong influence on the nanowire growth kinetics, reactor size has typically not been taken into account in the theoretical modeling developed so far. We report a new theoretical description of the axial growth rate of nanowires in dynamic conditions based on the solution of Fick's diffusion equations, implementing a sealed reactor of finite height as a varying parameter.

Chemical Bath Deposition of ZnO Nanowires Using Copper Nitrate as an Additive for Compensating Doping.

The controlled incorporation of dopants like copper into ZnO nanowires (NWs) grown by chemical bath deposition (CBD) is still challenging despite its critical importance for the development of piezoelectric devices. In this context, the effects of the addition of copper nitrate during the CBD of ZnO NWs grown on Au seed layers are investigated in detail, where zinc nitrate and hexamethylenetetramine are used as standard chemical precursors and ammonia as an additive to tune the pH. By combining thermodynamic simulations with chemical and structural analyses, we show that copper oxide nanocrystals simultaneously form with ZnO NWs during the CBD process in the low-pH region associated with large supersaturation of Cu species.

DNA Origami for Silicon Patterning.

Desoxyribonucleic acid (DNA) origami architectures are a promising tool for ultimate lithography because of their ability to generate nanostructures with a minimum feature size down to 2 nm. In this paper, we developed a method for silicon (Si) nanopatterning to face up current limitations for high-resolution patterning with standard microelectronic processes. For the first time, a 2 nm-thick 2D DNA origami mask, with specific design composed of three different square holes (with a size of 10 and 20 nm), is used for positive pattern transfer into a Si substrate using a 15 nm-thick silicon dioxide (SiO) layer as an intermediate hard mask.

Formation mechanisms of ZnO nanowires on polycrystalline Au seed layers for piezoelectric applications.

ZnO nanowires are considered as attractive building blocks for piezoelectric devices, including nano-generators and stress/strain sensors. However, their integration requires the use of metallic seed layers, on top of which the formation mechanisms of ZnO nanowires by chemical bath deposition are still largely open. In order to tackle that issue, the nucleation and growth mechanisms of ZnO nanowires on top of Au seed layers with a thickness in the range of 5-100 nm are thoroughly investigated.

Metallic Conductive Nanowires Elaborated by PVD Metal Deposition on Suspended DNA Bundles.

Metallic conductive nanowires (NWs) with DNA bundle core are achieved, thanks to an original process relying on double-stranded DNA alignment and physical vapor deposition (PVD) metallization steps involving a silicon substrate. First, bundles of DNA are suspended with a repeatable process between 2 µm high parallel electrodes with separating gaps ranging from 800 nm to 2 µm. The process consists in the drop deposition of a DNA lambda-phage solution on the electrodes followed by a naturally evaporation step.

DNA Origami Mask for Sub-Ten-Nanometer Lithography.

DNA nanotechnology is currently widely explored and especially shows promises for advanced lithography due to its ability to define nanometer scale features. We demonstrate a 9 × 14 nm(2) hole pattern transfer from DNA origami into an SiO2 layer with a sub-10-nm resolution using anhydrous HF vapor in a semiconductor etching machine. We show that the resulting SiO2 pattern inherits its shape from the DNA structure within a process time ranging from 30 to 60 s at an etching rate of 0.