Elwha LLC

Government of the United States of America, As Represented by the Secretary of Commerce

University System of Maryland

Fred Sharifi

Rachel Cannara

Emma Rae Mullen

Myung-Gyu Kang

Henri Lezec

Alex Smolyanitsky

Henry Lezec

Zhao Deng

The present disclosure relates to methods of fabricating a porous structure, such as a porous silicon carbide structure. The methods can include a step of providing a structure to be rendered porous, and a step of providing an etching solution. The methods can also include a step of electrochemically etching the structure to produce pores through at least a region of the structure, resulting in the formation of a porous structure. The morphology of the porous structure can be controlled by one or more parameters of the electrochemical etching process, such as the strength of the etching solution and/or the applied voltage.

Methods for fabricating and etching porous silicon carbide structures

A detection pixel includes a material that is chosen so that its (averaged) atomic number density leads to the Compton process being the dominant scattering mechanism in response to incident photons, leading to production of Compton electrons with sufficient number and kinetic energy to produce an electric or magnetic response in the material. The incident photon and Compton electrons each have a characteristic travel distance in the material, and the detection pixel has at least one dimension that is selected according to a range defined by these characteristic travel distances. The detection pixels may be arranged in an array for imaging.

High efficiency photon detection

The present disclosure relates to methods of making a transition metal dichalcogenide. The methods can include a step of depositing a transition metal onto a substrate to form an epitaxial transition metal layer. The methods can also include a step of depositing a chalcogen onto the epitaxial transition metal layer, and a step of reacting the chalcogen with the epitaxial transition metal layer to form a transition metal dichalcogenide. In some instances, the chalcogen is reacted with the epitaxial transition metal layer at a temperature of between about 300&#xb0; C. and 600&#xb0; C., between about 300&#xb0; C. and 550&#xb0; C., between about 300&#xb0; C. and 500&#xb0; C., between about 300&#xb0; C. and 450&#xb0; C., or between about 300&#xb0; C. and 400&#xb0; C.

Method for synthesis of two-dimensional dichalcogenide semiconductors

A cold cathode field emission electron source capable of emission at levels comparable to thermal sources is described. Emission in excess of 6 A/cmat 7.5 V/&#x3bc;m is demonstrated in a macroscopic emitter array. The emitter has a monolithic and rigid porous semiconductor nanostructure with uniformly distributed emission sites, and is fabricated through a room temperature process which allows for control of emission properties. These electron sources can be used in a wide range of applications, including microwave electronics and x-ray imaging for medicine and security.

Cold field electron emitters based on silicon carbide structures

A cold cathode field emission electron source capable of emission at levels comparable to thermal sources is described. Emission in excess of 6 A/cmat 7.5 V/&#x3bc;m is demonstrated in a macroscopic emitter array. The emitter is comprised of a monolithic and rigid porous semiconductor nanostructure with uniformly distributed emission sites, and is fabricated through a room temperature process which allows for control of emission properties. These electron sources can be used in a wide range of applications, including microwave electronics and x-ray imaging for medicine and security.

A variable temperature assembly for scanning probe microscopy (SPM) is described which minimizes or eliminates motion of the sample caused by the thermal expansion or contraction of the sample holder assembly and platform/scanning stage on which the assembly is mounted, and minimizes heating or cooling of the platform/stage. In heater form, the variable temperature assembly includes a thin boron nitride puck with one or more high-resistivity wires embedded along an underside of the puck. The puck is suspended from its polished top surface by posts that are secured to the microscope stage. All thermal expansion of the puck occurs in the downward direction, away from the SPM probe-sample interface, thus eliminating relative motion between the probe tip and sample surface. The top surface of the puck remains stationary as a result of the unique geometry of the posts and the puck-post attachment configuration described herein.

Growing community of inventors

Kirkland, WA, United States of America

Fred Sharifi