Abstract: Some embodiments include a method. The method can include: providing a carrier substrate; forming a first device material over the carrier substrate; and after forming the first device material over the carrier substrate, transforming the first device material into a second device material. Meanwhile, the transforming the first device material into the second device material can include: causing a cationic exchange in the first device material; and causing an anionic exchange in the first device material. The causing the cationic exchange in the first device material and the causing the anionic exchange in the first device material can occur approximately simultaneously. Other embodiments of related methods and systems are also disclosed.

Abstract: Reusable nanostructured substrates for forming semiconductor thin films, such as those used in solar cells, are configured with nanopillars to permit improved lift-off of thin films.

Abstract: Reusable nanostructured substrates for forming semiconductor thin films, such as those used in solar cells, are configured with nanopillars to permit improved lift-off of thin films.

Abstract: Embodiments of the invention provide a ceramic composites and synthesis methods that include providing a plurality of nanoparticles with at least one first rare-earth single-crystal compound, and mixing the plurality of nanoparticles with at least one ceramic material and at least one ceramic binder including at least one solvent. The method further includes preparing a ceramic green-body from the mixture, and sintering the ceramic green-body to form a ceramic composite of a polycrystalline ceramic with a plurality of embedded single-crystal nanorods. The embedded single-crystal nanorods include at least one second rare-earth single crystal compound. The at least one second rare-earth single crystal compound can include or be derived from the at least one first rare-earth single crystal compound.

Abstract: Some embodiments include a method. The method can include: providing a carrier substrate; forming a first device material over the carrier substrate; and after forming the first device material over the carrier substrate, transforming the first device material into a second device material. Meanwhile, the transforming the first device material into the second device material can include: causing a cationic exchange in the first device material; and causing an anionic exchange in the first device material. The causing the cationic exchange in the first device material and the causing the anionic exchange in the first device material can occur approximately simultaneously. Other embodiments of related methods and systems are also disclosed.

Abstract: Described herein are semiconductor structures comprising laterally varying II-VI alloy layer formed over a surface of a substrate. Further, methods are provided for preparing laterally varying II-VI alloy layers over at least a portion of a surface of a substrate comprising contacting at least a portion of a surface of a substrate within a reaction zone with a chemical vapor under suitable reaction conditions to form a laterally varying II-VI alloy layer over the portion of the surface of the substrate, wherein the chemical vapor is generated by heating at least two II-VI binary compounds; and the reaction zone has a temperature gradient of at least 50-100° C. along an extent of the reaction zone. Also described here are devices such as lasers, light emitting diodes, detectors, or solar cells that can use such semiconductor structures.

Abstract: Embodiments of the invention provide a ceramic composites and synthesis methods that include providing a plurality of nanoparticles with at least one first rare-earth single-crystal compound, and mixing the plurality of nanoparticles with at least one ceramic material and at least one ceramic binder including at least one solvent. The method further includes preparing a ceramic green-body from the mixture, and sintering the ceramic green-body to form a ceramic composite of a polycrystalline ceramic with a plurality of embedded single-crystal nanorods. The embedded single-crystal nanorods include at least one second rare-earth single crystal compound. The at least one second rare-earth single crystal compound can include or be derived from the at least one first rare-earth single crystal compound.

Abstract: Described herein are multi-segmented nanowires, nanosheets and nanobelts, and devices and methods using them for the generation of multicolor and white light.

Abstract: Described herein are multi-segmented nanowires, nanosheets and nanobelts, and devices and methods using them for the generation of multicolor and white light.

Abstract: A solar cell assembly can be prepared having one or more laterally-arranged multiple bandgap (LAMB) solar cells and a dispersive concentrator positioned to provide light to a surface of each of the LAMB cells. As described herein, each LAMB cell comprises a plurality of laterally-arranged solar cells each having a different bandgap.

Abstract: Described herein are semiconductor structures comprising laterally varying II-VI alloy layer formed over a surface of a substrate. Further, methods are provided for preparing laterally varying II-VI alloy layers over at least a portion of a surface of a substrate comprising contacting at least a portion of a surface of a substrate within a reaction zone with a chemical vapor under suitable reaction conditions to form a laterally varying II-VI alloy layer over the portion of the surface of the substrate, wherein the chemical vapor is generated by heating at least two II-VI binary compounds; and the reaction zone has a temperature gradient of at least 50-100° C. along an extent of the reaction zone. Also described here are devices such as lasers, light emitting diodes, detectors, or solar cells that can use such semiconductor structures.

Abstract: A method for converting a Type 2 quantum well semiconductor material to a Type 1 material. A second layer of undoped material is placed between first and third layers of selectively doped material, which are separated from the second layer by undoped layers having small widths. Doping profiles are chosen so that a first electrical potential increment across a first layer-second layer interface is equal to a first selected value and/or a second electrical potential increment across a second layer-third layer interface is equal to a second selected value. The semiconductor structure thus produced is useful as a laser material and as an incident light detector material in various wavelength regions, such as a mid-infrared region.

Abstract: Ultrafast directional beam switching is achieved using coupled VCSELs. This approach is demonstrated to achieve beam switching frequencies of 40 GHz and more and switching directions of about eight degrees. This switching scheme is likely to be useful for ultrafast optical networks at frequencies much higher than achievable with other approaches.

Abstract: An MFA-MOPA that includes a semiconductor laser with separate master oscillator and trumpet-flared power amplifier regions. Within the trumpet-flared active gain region of the uniformly-pumped power amplifier of the MFA-MOPA device, the density distribution of carriers and reflections of the laser beam are analyzed to determine the output powers at which filamentation and beam degradation due to reflections occur. The shape of the trumpet-flare is optimized to delay the onset of filamentation and the degradation of the output laser beam due to reflections to higher output powers for the MFA-MOPA device.