In one instance, the seed crystal of this invention provides a nitrogen-polar c-plane surface of a GaN layer supported by a metallic plate. The coefficient of thermal expansion of the metallic plate matches that of GaN layer. The GaN layer is bonded to the metallic plate with bonding metal. The bonding metal not only bonds the GaN layer to the metallic plate but also covers the entire surface of the metallic plate to prevent corrosion of the metallic plate and optionally spontaneous nucleation of GaN on the metallic plate during the bulk GaN growth in supercritical ammonia. The bonding metal is compatible with the corrosive environment of ammonothermal growth.

A method for applying a masked overgrowth layer onto a seed layer for producing semiconductor components, characterized in that a mask for masking the overgrowth layer is imprinted onto the seed layer.

A method for applying a masked overgrowth layer onto a seed layer for producing semiconductor components, characterized in that a mask for masking the overgrowth layer is imprinted onto the seed layer.

A method for using gallium beam flux in an ultra-low vacuum environment to etch Ga2O3 epilayer surfaces is provided. An Ga2O3 epilayer surface (105) is patterned by applying a SiO2 mask (107) that corresponds to a desired structure (810). The patterned surface is then placed in an ultra-low vacuum environment (130) and is heated to a very high temperature (820; 830). At the same time, a gallium flux is supplied to the patterned surface in the ultra-low vacuum environment (840). The gallium flux causes etching in the patterned surface that is not covered by the SiO2 mask. Using this method, sub-micron (?100 nm) three-dimensional (3D) structures like fins, trenches, and nano-pillars can be fabricated with vertical sidewalls.

Techniques, systems, and devices are disclosed for implementing light-emitting hyperbolic metasurfaces. In one exemplary aspect, a light-emitting device includes a surface; a plurality of quantum heterostructures positioned on the surface, each of the plurality of quantum heterostructures including multiple quantum wells distributed along an axis perpendicular to the surface and separated by multiple quantum barriers, wherein each two adjacent quantum heterostructures of the plurality quantum heterostructures form a gap; and a monocrystalline material at least partially filling gaps between the plurality quantum heterostructures.

Techniques, systems, and devices are disclosed for implementing light-emitting hyperbolic metasurfaces. In one exemplary aspect, a light-emitting device includes a surface; a plurality of quantum heterostructures positioned on the surface, each of the plurality of quantum heterostructures including multiple quantum wells distributed along an axis perpendicular to the surface and separated by multiple quantum barriers, wherein each two adjacent quantum heterostructures of the plurality quantum heterostructures form a gap; and a monocrystalline material at least partially filling gaps between the plurality quantum heterostructures.

Methods for large-scale manufacturing of semipolar gallium nitride boules are disclosed. The disclosed methods comprise suspending large-area single crystal seed plates in a rack, placing the rack in a large diameter autoclave or internally-heated high pressure apparatus along with ammonia and a mineralizer, and growing crystals ammonothermally. A bi-faceted growth morphology may be maintained to facilitate fabrication of large area semipolar wafers without growing thick boules.

Methods for large-scale manufacturing of semipolar gallium nitride boules are disclosed. The disclosed methods comprise suspending large-area single crystal seed plates in a rack, placing the rack in a large diameter autoclave or internally-heated high pressure apparatus along with ammonia and a mineralizer, and growing crystals ammonothermally. A bi-faceted growth morphology may be maintained to facilitate fabrication of large area semipolar wafers without growing thick boules.

A strip of sacrificial semiconductor material is formed on top of a non-sacrificial semiconductor material substrate layer. A conformal layer of the non-sacrificial semiconductor material is epitaxially grown to cover the substrate layer and the strip of sacrificial semiconductor material. An etch is performed to selectively remove the strip of sacrificial semiconductor material and leave a hollow channel surrounded by the conformal layer and the substrate layer. Using an anneal, the conformal layer and the substrate layer are reflowed to produce an optical waveguide structure including the hollow channel.

A strip of sacrificial semiconductor material is formed on top of a non-sacrificial semiconductor material substrate layer. A conformal layer of the non-sacrificial semiconductor material is epitaxially grown to cover the substrate layer and the strip of sacrificial semiconductor material. An etch is performed to selectively remove the strip of sacrificial semiconductor material and leave a hollow channel surrounded by the conformal layer and the substrate layer. Using an anneal, the conformal layer and the substrate layer are reflowed to produce an optical waveguide structure including the hollow channel.