The disclosure provides a thermoelectric conversion structure and its use in heat dissipation device. The thermoelectric conversion structure includes a thermoelectric element, a first electrode and an electrically conductive heat-blocking layer. The thermoelectric element includes a first end and a second end opposite to each other. The first electrode is located at the first end of the thermoelectric element. The electrically conductive heat-blocking layer is between the thermoelectric element and the first electrode.

An array of sensor devices, each sensor including a set of semiconducting nanotraces having a width less than about 100 nm is provided. Method for fabricating the arrays is disclosed, providing a top-down approach for large arrays with multiple copies of the detection device in a single processing step. Nanodimensional sensing elements with precise dimensions and spacing to avoid the influence of electrodes are provided. The arrays may be used for multiplex detection of chemical and biomolecular species. The regular arrays may be combined with parallel synthesis of anchor probe libraries to provide a multiplex diagnostic device. Applications for gas phase sensing, chemical sensing and solution phase biomolecular sensing are disclosed.

Metal oxide nanostructure and methods of making metal oxide nanostructures are provided. The metal oxide nanostructures can be 1-dimensional nanostructures such as nanowires, nanofibers, or nanotubes. The metal oxide nanostructures can be doped or un-doped metal oxides. The metal oxide nanostructures can be deposited onto a variety of substrates. The deposition can be performed without high pressures and without the need for seed catalysts on the substrate. The deposition can be performed by laser ablation of a target including a metal oxide and, optionally, a dopant. In some embodiments zinc oxide nanostructures are deposited onto a substrate by pulsed laser deposition of a zinc oxide target using an excimer laser emitting UV radiation. The zinc oxide nanostructure can be doped with a rare earth metal such as gadolinium. The metal oxide nanostructures can be used in many devices including light-emitting diodes and solar cells.

A process for etching a substrate comprising polycrystalline silicon to form silicon nanostructures includes depositing metal on top of the substrate and contacting the metallized substrate with an etchant aqueous solution comprising about 2 to about 49 weight percent HF and an oxidizing agent.

The absorbance or emission wavelength of composite materials comprising a transition metal doped shell disposed over a rare earth doped core and a functionalizable group on the surface of the transition metal doped shell can change upon subjection to a carboxylic acid. This method of changing the absorbance or emission wavelength of a composite material can be used to identify counterfeit currency using an ink comprising a composite material.

This disclosure provides systems, methods, and apparatus related to boron nitride nanomaterials. In one aspect, a method includes generating a directed flow of plasma. A boron-containing species is introduced to the directed flow of the plasma. Boron nitride nanostructures are formed in a chamber. In another aspect, a method includes generating a directed flow of plasma using nitrogen gas. A boron-containing species is introduced to the directed flow of the plasma. The boron-containing species can consist of boron powder, boron nitride powder, and/or boron oxide powder. Boron nitride nanostructures are formed in a chamber, with a pressure in the chamber being about 3 atmospheres or greater.

A method of fabricating a transparent conductor is provided. The method includes forming a nanowire dispersion layer on a substrate, forming a nanowire network layer on the substrate by drying the nanowire dispersion layer, and forming a matrix material layer on the nanowire network layer.

A method is presented for forming a nanowire electrode. The method includes forming a plurality of nanowires over a first substrate, depositing a conducting layer over the plurality of nanowires, forming solder bumps and electrical interconnections over a second flexible substrate, and integrating nanowire electrode arrays to the second flexible substrate. The plurality of nanowires are silicon (Si) nanowires, the Si nanowires used as probes to penetrate skin of a subject to achieve electrical biopotential signals. The plurality of nanowires are formed over the first substrate by metal-assisted chemical etching.

The absorbance or emission wavelength of composite materials comprising a transition metal doped shell disposed over a rare earth doped core and a functionalizable group on the surface of the transition metal doped shell can change upon subjection to a carboxylic acid. This method of changing the absorbance or emission wavelength of a composite material can be used to identify counterfeit currency using an ink comprising a composite material.

A semiconductor device includes a drain, a source, a gate electrode, and a nanowire between the source and drain. The nanowire has a first section with a first thickness and a second section with a second thickness greater than the first thickness. The second section is between the first section and at least one of the source or drain. The first nanowire includes a channel when a voltage is applied to the gate electrode.