Provided herein are methods for forming one or more silicon nanostructures, such as silicon nanotubes, and a silica-containing glass substrate. As a result of the process used to prepare the silicon nanostructures, the silica-containing glass substrate comprises one or more nanopillars and the one or more silicon nanostructures extend from the nanopillars of the silica-containing glass substrate. The silicon nanostructures include nanotubes and optionally nanowires. A further aspect is a method for preparing silicon nanostructures on a silica-containing glass substrate. The method includes providing one or more metal nanoparticles on a silica-containing glass substrate and then performing reactive ion etching of the silica-containing glass substrate under conditions that are suitable for the formation of one or more silicon nanostructures.

Provided herein are methods for forming one or more silicon nanostructures, such as silicon nanotubes, and a silica-containing glass substrate. As a result of the process used to prepare the silicon nanostructures, the silica-containing glass substrate comprises one or more nanopillars and the one or more silicon nanostructures extend from the nanopillars of the silica-containing glass substrate. The silicon nanostructures include nanotubes and optionally nanowires. A further aspect is a method for preparing silicon nanostructures on a silica-containing glass substrate. The method includes providing one or more metal nanoparticles on a silica-containing glass substrate and then performing reactive ion etching of the silica-containing glass substrate under conditions that are suitable for the formation of one or more silicon nanostructures.

Provided herein are methods for forming one or more silicon nanostructures, such as silicon nanotubes, and a silica-containing glass substrate. As a result of the process used to prepare the silicon nanostructures, the silica-containing glass substrate comprises one or more nanopillars and the one or more silicon nanostructures extend from the nanopillars of the silica-containing glass substrate. The silicon nanostructures include nanotubes and optionally nanowires. A further aspect is a method for preparing silicon nanostructures on a silica-containing glass substrate. The method includes providing one or more metal nanoparticles on a silica-containing glass substrate and then performing reactive ion etching of the silica-containing glass substrate under conditions that are suitable for the formation of one or more silicon nanostructures.

Provided herein are methods for forming one or more silicon nanostructures, such as silicon nanotubes, and a silica-containing glass substrate. As a result of the process used to prepare the silicon nanostructures, the silica-containing glass substrate comprises one or more nanopillars and the one or more silicon nanostructures extend from the nanopillars of the silica-containing glass substrate. The silicon nanostructures include nanotubes and optionally nanowires. A further aspect is a method for preparing silicon nanostructures on a silica-containing glass substrate. The method includes providing one or more metal nanoparticles on a silica-containing glass substrate and then performing reactive ion etching of the silica-containing glass substrate under conditions that are suitable for the formation of one or more silicon nanostructures.

The invention provides a micron-scale monocrystal film. The micron-scale monocrystal film includes 1) a substrate layer, and 2) a micron-scale monocrystal film layer located on the substrate layer, wherein a transition layer is interposed between the substrate layer and micron-scale monocrystal film layer, and the transition layer may include a first transition layer disposed adjacent to the substrate layer and a second transition layer disposed adjacent to the micron monocrystal film layer, wherein the transition layer may include H and an element from at least one kind of plasma gas used during the plasma bonding of the substrate layer and the micron-scale monocrystal film layer.

The invention provides a micron-scale monocrystal film. The micron-scale monocrystal film includes 1) a substrate layer, and 2) a micron-scale monocrystal film layer located on the substrate layer, wherein a transition layer is interposed between the substrate layer and micron-scale monocrystal film layer, and the transition layer may include a first transition layer disposed adjacent to the substrate layer and a second transition layer disposed adjacent to the micron monocrystal film layer, wherein the transition layer may include H and an element from at least one kind of plasma gas used during the plasma bonding of the substrate layer and the micron-scale monocrystal film layer.

Provided herein are methods for forming one or more silicon nanostructures, such as silicon nanotubes, and a silica-containing glass substrate. As a result of the process used to prepare the silicon nanostructures, the silica-containing glass substrate comprises one or more nanopillars and the one or more silicon nanostructures extend from the nanopillars of the silica-containing glass substrate. The silicon nanostructures include nanotubes and optionally nanowires. A further aspect is a method for preparing silicon nanostructures on a silica-containing glass substrate. The method includes providing one or more metal nanoparticles on a silica-containing glass substrate and then performing reactive ion etching of the silica-containing glass substrate under conditions that are suitable for the formation of one or more silicon nanostructures.

Provided herein are methods for forming one or more silicon nanostructures, such as silicon nanotubes, and a silica-containing glass substrate. As a result of the process used to prepare the silicon nanostructures, the silica-containing glass substrate comprises one or more nanopillars and the one or more silicon nanostructures extend from the nanopillars of the silica-containing glass substrate. The silicon nanostructures include nanotubes and optionally nanowires. A further aspect is a method for preparing silicon nanostructures on a silica-containing glass substrate. The method includes providing one or more metal nanoparticles on a silica-containing glass substrate and then performing reactive ion etching of the silica-containing glass substrate under conditions that are suitable for the formation of one or more silicon nanostructures.

A composite substrate of the present disclosure is a composite substrate comprising a piezoelectric substrate and a sapphire substrate which are directly bonded, wherein the ratio of the number of oxygen atoms to the number of aluminum atoms in the bonding surface region including the bonding surface of the sapphire substrate bonded to the piezoelectric substrate is less than 1.5. The piezoelectric device of the present disclosure comprises the composite substrate. A method for manufacturing the composite substrate of the present disclosure comprises a step of preparing a piezoelectric substrate and a sapphire substrate, a step of heat-treating the sapphire substrate in a reducing atmosphere or in a vacuum, and a step of directly bonding the piezoelectric substrate to the sapphire substrate.

A bonded body includes a supporting substrate; a piezoelectric material substrate composed of a material selected from the group consisting of lithium niobate, lithium tantalate and lithium niobate-lithium tantalate; and a bonding layer bonding the supporting substrate and the piezoelectric material substrate and contacting a main surface of the piezoelectric material substrate. The bonding layer includes a void extending from the piezoelectric material substrate to the supporting substrate.