Abstract: A reconfigurable optical frequency selective structure having embedded therein: (a) an array of optical antennas for picking up propagating radiation in a visible or infrared frequency region and achieving preferential absorption of electromagnetic energy at a target wavelength k within the region, (b) an array of optical mesa structures of sub-wavelength scale including a phase-change material, the array of optical antennas being disposed atop the array of optical mesa structures respectively; (c) a metal ground plane disposed beneath the array of optical mesa structures, the array of optical mesa structures standing above the ground plane or an interfacial layer and being separated from one another to inhibit parasitic capacitance coupling therebetween; and (d) a plurality of heaters for selectively heating any one of the array of optical mesa structures to cause the phase change material in the selected optical mesa structure to change from an amorphous state, wherein the antenna atop the selected mesa

Abstract: A process enables growing thick stoichiometric crystalline and preferably IR-transparent optical PCMO material on Si and other substrates. Sputter deposition is carried out in oxygen-free inert gas (e.g., Ar) environment, which helps to prevent decomposition of the PCMO material over the substrate. In the disclosed process, there is no need to add a seed layer prior to PCMO deposition. Moreover, no post-deposition annealing is needed in a high-temperature and high-pressure oxygen furnace, but an anneal provides certain additional benefits in terms of improved transparency at IR wavelengths. Over a long deposition time for a thick PCMO film on the high temperature (?450° C.) substrates, the PCMO deposition is made repeated cycles of deposition of the PCMO material at the high temperature, each deposition cycle being followed by cooling the PCMO-deposited substrate to a substantially lower temperature (<50° C.).

Abstract: A transition metal dichalcogenide (TMD) transistor includes a substrate, an n-type two-dimensional (2D) TMD layer, a metal source electrode, a metal drain electrode, and a gate dielectric. The substrate has a top portion that is an insulating layer, and the n-type 2D TMD layer is on the insulating layer. The metal source electrode, the metal drain electrode, and the gate dielectric are on the n-type 2D TMD layer. The metal gate electrode is on top of the gate dielectric and is between the metal source electrode and the metal drain electrode.

Abstract: An electric field-controlled refractive index tunable device includes a phase change correlated transition metal oxide layer, and E-field responsive charge dopants. The E-field responsive charge dopants either accumulate in the phase change correlated transition metal oxide layer or are depleted from the phase change correlated transition metal oxide layer in response to an E-field applied to the phase change correlated transition metal oxide layer.

Abstract: A transition metal dichalcogenide (TMD) transistor includes a substrate, an n-type two-dimensional (2D) TMD layer, a metal source electrode, a metal drain electrode, and a gate dielectric. The substrate has a top portion that is an insulating layer, and the n-type 2D TMD layer is on the insulating layer. The metal source electrode, the metal drain electrode, and the gate dielectric are on the n-type 2D TMD layer. The metal gate electrode is on top of the gate dielectric and is between the metal source electrode and the metal drain electrode.

Abstract: A solid state optical beam steering device including a body of electro-optical material wherein the body of electro-optical material comprises any material of a class of hydrogen-doped phase-change metal oxide and wherein the body has a first face and a second face opposite the first face, a first transparent resistive sheet on the first face of the body of electro optic material, wherein the first transparent resistive sheet has a first side and a second side, and a transparent conductor on the second face of the body of electro optic material, wherein the transparent conductor is coupled to the second side of the first transparent resistive sheet.

Abstract: A method of providing a spatial light modulator comprising: providing a substrate; providing a first phase change material cell on the substrate, the first phase change material cell comprising: a first electrical heater on the substrate; a first optical reflector layer on the electrical heater; and a first phase change material layer on the optical reflector layer; and providing at least a second phase change material cell on the substrate, the second phase change material cell comprising: a second electrical heater on the substrate; a second optical reflector layer on the second electrical heater; a second phase change material layer on the second optical reflector layer; and providing a light absorber layer between the first phase change material cell and the second phase change material cell.

Abstract: A process enables growing thick stoichiometric crystalline and preferably IR-transparent optical PCMO material on Si and other substrates. Sputter deposition is carried out in oxygen-free inert gas (e.g., Ar) environment, which helps to prevent decomposition of the PCMO material over the substrate. In the disclosed process, there is no need to add a seed layer prior to PCMO deposition. Moreover, no post-deposition annealing is needed in a high-temperature and high-pressure oxygen furnace, but an anneal provides certain additional benefits in terms of improved transparency at IR wavelengths. Over a long deposition time for a thick PCMO film on the high temperature (?450° C.) substrates, the PCMO deposition is made repeated cycles of deposition of the PCMO material at the high temperature, each deposition cycle being followed by cooling the PCMO-deposited substrate to a substantially lower temperature (<50° C.).

Abstract: A method of fabricating a gate with a mini field plate includes forming a dielectric passivation layer over an epitaxy layer on a substrate, coating the dielectric passivation layer with a first resist layer, etching the first resist layer and the dielectric passivation layer to form a first opening in the dielectric passivation layer, removing the first resist layer; and forming a tri-layer gate having a gate foot in the first opening, the gate foot having a first width, a gate neck extending from the gate foot and extending for a length over the dielectric passivation layer on both sides of the first opening, the gate neck having a second width wider than the first width of the gate foot, and a gate head extending from the gate neck, the gate head having a third width wider than the second width of the gate neck.

Abstract: A field effect transistor includes a substrate, a passivation layer on the substrate forming a passivated substrate, wherein the passivation layer is inert to XeF2, and a graphene lateral heterostructure field effect transistor (LHFET) on the passivated substrate.

Abstract: A process enables growing thick stoichiometric crystalline and preferably IR-transparent optical PCMO material on Si and other substrates. Sputter deposition is carried out in oxygen-free inert gas (e.g., Ar) environment, which helps to prevent decomposition of the PCMO material over the substrate. In the disclosed process, there is no need to add a seed layer prior to PCMO deposition. Moreover, no post-deposition annealing is needed in a high-temperature and high-pressure oxygen furnace, but an anneal provides certain additional benefits in terms of improved transparency at IR wavelengths. Over a long deposition time for a thick PCMO film on the high temperature (?450° C.) substrates, the PCMO deposition is made repeated cycles of deposition of the PCMO material at the high temperature, each deposition cycle being followed by cooling the PCMO-deposited substrate to a substantially lower temperature (<50° C.).

Abstract: A solid state electrically variable focal length lens includes a plurality of concentric rings of electro-optical material, wherein the electro-optical material comprises any material of a class of hydrogen-doped phase-change metal oxide and wherein each respective concentric ring further includes a transparent resistive sheet on a first face of the respective concentric ring, wherein the transparent resistive sheet extends along the first face, and a first voltage coupled between a first end and a second end of the transparent resistive sheet, wherein the first voltage may be varied to select an optical beam deflection angle.

Abstract: A solid state electrically variable focal length lens includes a plurality of concentric rings of electro-optical material, wherein the electro-optical material comprises any material of a class of hydrogen-doped phase-change metal oxide and wherein each respective concentric ring further includes a transparent resistive sheet on a first face of the respective concentric ring, wherein the transparent resistive sheet extends along the first face, and a first voltage coupled between a first end and a second end of the transparent resistive sheet, wherein the first voltage may be varied to select an optical beam deflection angle.

Abstract: A HEMT comprising: a substrate; a channel layer coupled to the substrate; a source electrode coupled to the channel layer; a drain electrode coupled to the channel layer; and a gate electrode coupled to the channel layer between the source electrode and the drain electrode; wherein the channel layer comprises: at least a first GaN layer; and a first graded AlGaN layer on the first GaN layer, the Al proportion of the first graded AlGaN layer increasing with the distance from the first GaN layer.

Abstract: A method of fabricating a gate with a mini field plate includes forming a dielectric passivation layer over an epitaxy layer on a substrate, coating the dielectric passivation layer with a first resist layer, etching the first resist layer and the dielectric passivation layer to form a first opening in the dielectric passivation layer, removing the first resist layer; and forming a tri-layer gate having a gate foot in the first opening, the gate foot having a first width, a gate neck extending from the gate foot and extending for a length over the dielectric passivation layer on both sides of the first opening, the gate neck having a second width wider than the first width of the gate foot, and a gate head extending from the gate neck, the gate head having a third width wider than the second width of the gate neck.

Abstract: A spatial light modulator cell and arrays of spatial light modulator cells are disclosed. The spatial light modulator cells can comprise a phase change material (PCM) having a first side and a second side; an optical reflector configured to reflect an optical beam passing from the first side to the second side; and a PCM heater thermal conductively coupled to the PCM, wherein thermal modulation of the PCM modulates a phase of the PCM which varies light transmission through the PCM. Methods of making spatial light modulator cells and arrays are also disclosed.

Abstract: A method of fabricating a gate with a mini field plate includes forming a dielectric passivation layer over an epitaxy layer on a substrate, coating the dielectric passivation layer with a first resist layer, etching the first resist layer and the dielectric passivation layer to form a first opening in the dielectric passivation layer, removing the first resist layer, and forming a tri-layer gate having a gate foot in the first opening, a gate neck extending from the gate foot, and a gate head extending from the gate neck. The gate foot has a first width, and the gate neck has a second width that is wider than the first width. The gate neck extends for a length over the dielectric passivation layer on both sides of the first opening. The gate head has a third width wider than the second width of the gate neck.

Abstract: A vertical directional coupler or switch comprising a lower and an upper waveguide, integrated with an optical phase change material disposed between the lower and upper waveguides to control a directional of optical coupling between the lower and upper waveguides.

Abstract: A Field Effect Transistor (FET) device and a method for manufacturing it are disclosed. The FET device contains a graphene layer, a composite gate dielectric layer disposed above the graphene layer, wherein the composite gate layer is passivated with fluorine, and a metal gate disposed above the composite gate dielectric layer. The method disclosed teaches how to manufacture the FET device.

Abstract: A spatial light modulator includes a substrate, a phase change material cell on the substrate, the phase change material cell including an electrical heater on the substrate, an optical reflector layer on the electrical heater, and a phase change material layer on the optical reflector layer.