Abstract: A light emitting diode array includes a growth mask having an array of closed shapes on a III-N layer. An array of group III-N inverted pyramids are epitaxially grown around the growth mask. The inverted pyramids include {10-11} or {11-22} facets and hexagonal bases. An array of III-N c-plane surfaces are parallel with the substrate and join the {10-11} or {11-22} facets of adjacent ones of the III-N inverted pyramids. A quantum well layer of a III-N compound is formed on the {10-11} or {11-22} facets and the c-plane surfaces. The quantum well layer has a first thickness on the {10-11} or {11-22} facets that forms first light emitting elements. The quantum well layer has a second thickness on the c-plane surfaces that forms second light emitting elements. The second light emitting elements emit light at a longer wavelength than the first light emitting elements.

Abstract: A semiconductor device is formed on a bulk substrate of n-type GaN. The semiconductor device has a material layer grown on the bulk substrate. A first surface of the bulk substrate facing away from the material layer is mechanically roughened and a negative electrical contact is formed on the roughened surface using a low work function metal.

Abstract: Ink-based digital printing systems useful for ink printing include a rotatable charge-retentive reimageable surface layer configured to receive a layer of fountain solution. The fountain solution is carried to the charge retentive surface by a fog or mist including fountain solution aerosol particles, dispersed gas particles, and charge directors that impart charge to the fountain solution aerosol particles. The charge-retentive reimageable surface may be charged to a uniform potential, and selectively discharged using an ROS according to image data to form an electrostatic latent image. The charged fountain solution adheres to portions of the charge-retentive reimageable surface according to the electrostatic latent image to form a fountain solution image thereon. The fountain solution image can be partially transferred to an imaging blanket, where the fountain solution image is inked. The resulting ink image may be transferred to a print substrate.

Abstract: A light emitting diode (LED) array includes bottom reflectors patterned as an array of closed shapes on a top plane of a base layer for III-N growth. A three-dimensional III-N structure is epitaxially grown around the array of closed shapes and extending above the bottom reflectors. The three-dimensional III-N structures is a contiguous crystalline structure extending across the array. A laterally grown III-N layer is formed in contact with both the reflectors and the three-dimensional III-N structures, and III-N LED layers are grown on the laterally grown layer. One or more top reflectors are grown or deposited on the III-N LED layers and located over the bottom reflectors.

Abstract: A transistor includes a first layer comprising a group III-nitride semiconductor. A second layer comprising a group III-nitride semiconductor is disposed over the first layer. A third layer comprising a group III-nitride semiconductor is disposed over the second layer. An interface between the second layer and the third layer form a polarization heterojunction. A fourth layer comprising a group III-nitride semiconductor is disposed over the third layer. An interface between the third layer and the fourth layer forms a pn junction. A first electrical contact pad is disposed on the fourth layer. A second electrical contact pad is disposed on the third layer. A third electrical contact pad is electronically coupled to bias the polarization heterojunction.

Abstract: An apparatus includes an epitaxial structure comprising a bottom layer, channel walls formed on the bottom layer, and a top layer that encloses the channel walls and forms microchannels therebetween. The bottom layer, channel walls, and covering layer are a monolithic, crystalline formation. An electronic or optoelectronic device is monolithically formed on a first build surface of the bottom layer or the top layer. The electronic or optoelectronic device is energy-coupled to the microchannels through the bottom layer or the top layer.

Abstract: Based on evaporation of fountain solution from a rotating blanket cylinder to create an image that may be inked and printed, a digitally addressable heater array at or just below the blanket surface evaporates deposited fountain solution and forms a fountain solution latent image on the surface. The heater array has controllable heating elements (e.g., field effect transistors, thin film transistors) that provide a transient heat pattern on the surface to evaporate the fountain solution. Heat is generated by current flow in the heating elements, and power developed by the heating circuit is the product of source-drain voltage and current in the channel. Current may be supplied along data lines by an external voltage controlled by digital electronics to provide the desired heat at heating elements addressed by a specific gate line. The heater array may include a current return line that may be a 2-dimensional mesh.

Abstract: A mask material is deposited on a substrate or growth template. The substrate or growth template is compatible with crystalline growth of a crystalline optical material. Patterned portions of the mask material are removed to expose one or more regions of the substrate or growth template. The one or more regions have target shapes of one or more optical components. The crystalline optical material is selectively grown in the one or more regions to form the one or more optical components.

Abstract: Based on evaporation of fountain solution from a rotating blanket cylinder to create an image that may be inked and printed, a digitally addressable heater array at or just below the blanket surface evaporates deposited fountain solution and forms a fountain solution latent image on the surface. The heater array has controllable heating elements (e.g., field effect transistors, thin film transistors) that provide a transient heat pattern on the surface to evaporate the fountain solution. Heat is generated by current flow in the heating elements, and power developed by the heating circuit is the product of source-drain voltage and current in the channel. Current may be supplied along data lines by an external voltage controlled by digital electronics to provide the desired heat at heating elements addressed by a specific gate line. The heater array may include a current return line that may be a 2-dimensional mesh.

Abstract: Ink-based digital printing systems useful for ink printing include a rotatable charge-retentive reimageable surface layer configured to receive a layer of fountain solution. The fountain solution is carried to the charge retentive surface by a fog or mist including fountain solution aerosol particles, dispersed gas particles, and charge directors that impart charge to the fountain solution aerosol particles. The charge-retentive reimageable surface may be charged to a uniform potential, and selectively discharged using an ROS according to image data to form an electrostatic latent image. The charged fountain solution adheres to portions of the charge-retentive reimageable surface according to the electrostatic latent image to form a fountain solution image thereon. The fountain solution image can be partially transferred to an imaging blanket, where the fountain solution image is inked. The resulting ink image may be transferred to a print substrate.

Abstract: Ink-based digital printing systems useful for ink printing include a secondary roller having a rotatable reimageable surface layer configured to receive fountain solution. The fountain solution layer is patterned on the secondary roller and then partially transferred to an imaging blanket, where the fountain solution image is inked. The resulting ink image may be transferred to a print substrate. To achieve a very high-resolution (e.g., 1200-dpi, over 900-dpi) print with these secondary roller configurations, an equivalent very high-resolution fountain solution image needs to be transferred from the secondary roller onto the imaging blanket. To increase the resolution of the image on the secondary roller, examples include a textured surface layer added to the secondary roller for contact angle pinning the fountain solution on the roll. Approaches to introduce a micro-structure onto the surface layer of the secondary roller, and also superoleophobic surface coatings are described.

Abstract: Methods and systems for disinfecting a surface, can include a light source, and a transparent window located above the light source. The light source can be integrated into an object, and an outer surface of the object can be located above the transparent window. Light from the light source can irradiate the outer surface through the transparent window and from within the object to disinfect the outer surface of the object. The light can comprise violet and ultraviolet (UV) light. A photocatalytic layer comprising a photocatalytic material may also be located above the transparent window and below the outer surface.

Abstract: An optical device has a first optical layer with a first dispersion response as a first function of wavelength. A second optical layer has a second dispersion response as a function of wavelength that is different than the first function. A separating layer is located between the first and second optical layers and has a lower refractive index than the first layer and the second layer. A thickness of the separating layer is selected such that the first and second dispersion responses combine to create an anomalous dispersion about a target wavelength. The anomalous dispersion results in the optical device emitting a wideband coherent optical output about the target wavelength in response to an optical input at the target wavelength.

Abstract: A transistor includes a first layer comprising a group III-nitride semiconductor. A second layer comprising a group III-nitride semiconductor is disposed over the first layer. A third layer comprising a group III-nitride semiconductor is disposed over the second layer. An interface between the second layer and the third layer form a polarization heterojunction. A fourth layer comprising a group III-nitride semiconductor is disposed over the third layer. An interface between the third layer and the fourth layer forms a pn junction. A first electrical contact pad is disposed on the fourth layer. A second electrical contact pad is disposed on the third layer. A third electrical contact pad is electronically coupled to bias the polarization heterojunction.

Abstract: A method of forming a laser involves forming, on a substrate, a first epitaxial part of the laser that includes at least an active region layer surrounded by first and second waveguide layers. A dielectric layer is formed over the first epitaxial part. Two or more mask openings are patterned within the dielectric layer. The mask openings extend normal to a light-propagation direction of the laser and are spaced apart in the light-propagation direction of the laser. A second epitaxial part of the laser is formed in the mask openings using selective area epitaxy. The second epitaxial part includes a refractive grating with three-dimensional grating features.

Abstract: A laser includes an active region surrounded by first and second waveguide layers. Two or more mask openings are formed within a dielectric layer on a surface parallel to the active region. A refractive grating is formed on the dielectric mask openings and includes three-dimensional grating features spaced apart in the light-propagation direction of the laser. The refractive grating provides modulation of a real part of the effective refractive index of the laser and modulation of the imaginary part is provided by modulation of the current flow through the mask openings.

Abstract: An optical device has a first optical layer with a first dispersion response as a first function of wavelength. A second optical layer has a second dispersion response as a function of wavelength that is different than the first function. A separating layer is located between the first and second optical layers and has a lower refractive index than the first layer and the second layer. A thickness of the separating layer is selected such that the first and second dispersion responses combine to create an anomalous dispersion about a target wavelength. The anomalous dispersion results in the optical device emitting a wideband coherent optical output about the target wavelength in response to an optical input at the target wavelength.

Abstract: A laser includes an active region surrounded by first and second waveguide layers. Two or more mask openings are formed within a dielectric layer on a surface parallel to the active region. A refractive grating is formed on the dielectric mask openings and includes three-dimensional grating features spaced apart in the light-propagation direction of the laser. The refractive grating provides modulation of a real part of the effective refractive index of the laser and modulation of the imaginary part is provided by modulation of the current flow through the mask openings.

Abstract: An ultraviolet (UV) radiation emitting device includes an epitaxial heterostructure comprising an AlGaInN active region. The AlGaInN active region includes one or more quantum well structures with Al content greater than about 50% and having a non-c-plane crystallographic growth orientation. The AlGaInN active region is configured to generate UV radiation in response to excitation by an electron beam generated by an electron beam pump source.

Abstract: An edge emitting structure includes an active region configured to generate radiation in response to excitation by a pumping beam incident on the structure. A front facet of the edge emitting structure is configured to emit the radiation generated by the active region. A metallic reflective coating disposed on at least one of the front and rear facets of the edge emitting structure. The metallic reflective coating is configured to reflect the radiation generated by the active region.