Abstract: Proposed is a layer structure (1100, 1030) comprising a crystalline piezoelectric III-N layer (1110, 1032) epitaxially grown over a metal layer which is epitaxially grown over a rare earth oxide layer on a semiconductor (1102, 1002). The rare earth oxide layer includes at least two discrete portions (1104, 1004), and the metal layer includes at least one metal portion (1108, 1006) that partially overlaps adjacent discrete portions, preferably forming a bridge over an air gap (1008), particularly suitable for RF filters.

Abstract: The structures and methods disclosed herein include changing composition of a metal alloy layer in an epitaxial electrode material to achieve tunable work functions for the electrode. In one example, the tunable work function is achieved using a layered structure, in which a crystalline rare earth oxide (REO) layer is epitaxially over a substrate or semiconductor, and a metal layer is over the crystalline REO layer. A semiconductor layer is thus in turn epitaxially grown over the metal layer, with a metal alloy layer over the semiconductor layer such that the ratio of constituents in the metal alloy is used to tune the work function of the metal layer.

Abstract: A photovoltaic device, particularly a solar cell, comprises an interface between a layer of Group III-V material and a layer of Group IV material with a thin silicon diffusion barrier provided at or near the interface. The silicon barrier controls the diffusion of Group V atoms into the Group IV material, which is doped n-type thereby. The n-type doped region can provide the p-n junction of a solar cell in the Group IV material with superior solar cell properties. It can also provide a tunnel diode in contact with a p-type region of the III-V material, which tunnel diode is also useful in solar cells.

Abstract: Systems and methods described herein may include a first semiconductor layer with a first lattice constant, a rare earth pnictide buffer epitaxially grown over the first semiconductor, wherein a first region of the rare earth pnictide buffer adjacent to the first semiconductor has a net strain that is less than 1%, a second semiconductor layer epitaxially grown over the rare earth pnictide buffer, wherein a second region of the rare earth pnictide buffer adjacent to the second semiconductor has a net strain that is a desired strain, and wherein the rare earth pnictide buffer may comprise one or more rare earth elements and one or more Group V elements. In some examples, the desired strain is approximately zero.

Abstract: A multijunction tandem photovoltaic device is disclosed having a bottom subcell of silicon germanium or silicon germanium tin material and above that a subcell of gallium nitride arsenide bismide, or indium gallium nitride arsenide bismide, material. The materials are lattice matched to gallium arsenide, which preferably forms the substrate. Preferably, further lattice matched subcells of gallium arsenide, indium gallium phosphide and aluminum gallium arsenide or aluminum indium gallium phosphide are provided.

Abstract: Systems and methods are described herein to include an epitaxial metal layer between a rare earth oxide and a semiconductor layer. Systems and methods are described to grow a layered structure, comprising a substrate, a first rare earth oxide layer epitaxially grown over the substrate, a first metal layer epitaxially grown over the rare earth oxide layer, and a first semiconductor layer epitaxially grown over the first metal layer.

Abstract: Layer structures for RF filters can be fabricated using rare earth oxides and epitaxial aluminum nitride, and methods for growing the layer structures. A layer structure can include an epitaxial crystalline rare earth oxide (REO) layer over a substrate, a first epitaxial electrode layer over the crystalline REO layer, and an epitaxial piezoelectric layer over the first epitaxial electrode layer. The layer structure can further include a second electrode layer over the epitaxial piezoelectric layer. The first electrode layer can include an epitaxial metal. The epitaxial metal can be single-crystal. The first electrode layer can include one or more of a rare earth pnictide, and a rare earth silicide (RESi).

Abstract: Nucleation layers for growth of III-nitride structures, and methods for growing the nucleation layers, are described herein. A semiconductor can include a silicon substrate and a nucleation layer over the silicon substrate. The nucleation layer can include silicon and deep-level dopants. The semiconductor can include a III-nitride layer formed over the nucleation layer. At least one of the silicon substrate and the nucleation layer can include ionized contaminants. In addition, a concentration of the deep-level dopants is at least as high as a concentration of the ionized contaminants.

Abstract: Optoelectronic detectors having one or more dilute nitride layers on substrates with lattice parameters matching or nearly matching GaAs are described herein. A semiconductor can include a substrate with a lattice parameter matching or nearly matching GaAs and a first doped III-V layer over the substrate. The semiconductor can also include an absorber layer over the first doped III-V layer, the absorber layer having a bandgap between approximately 0.7 eV and 0.95 eV and a carrier concentration less than approximately 1×1016 cm?3 at room temperature. The semiconductor can also include a second doped III-V layer over the absorber layer.

Abstract: A photovoltaic device comprises an interface (8) between a layer of Group III-V material (3) and a layer of Group IV material (1) with a thin silicon diffusion barrier (6) provided at or near the interface. The silicon barrier controls the diffusion of Group V atoms into the Group IV material, which is doped n-type thereby. The n-type doped region can provide the p-n junction of a solar cell in the Group IV material with superior solar cell properties. It can also provide a tunnel diode in contact with a p-type region of the III-V material, which tunnel diode is also useful in solar cells. In another aspect, a multijunction photovoltaic device is provided in which there are at least a first light-absorbing layer (111) of SiGe or SiGeSn and a second light-absorbing layer (112) of SiGeSn, both layers being lattice-matched to GaAs.

Abstract: A multijunction tandem photovoltaic device is disclosed having a bottom subcell of silicon germanium or silicon germanium tin material and above that a subcell of gallium nitride arsenide antimonide material. The materials are lattice matched to gallium arsenide, which preferably forms the substrate. Preferably, further lattice matched subcells of gallium arsenide, indium gallium phosphide and aluminium gallium arsenide or aluminium indium gallium phosphide are provided.

Abstract: A multijunction tandem photovoltaic device is disclosed having a bottom subcell of silicon germanium or silicon germanium tin material and above that a subcell of gallium nitride arsenide bismide, or indium gallium nitride arsenide bismide, material. The materials are lattice matched to gallium arsenide, which preferably forms the substrate. Preferably, further lattice matched subcells of gallium arsenide, indium gallium phosphide and aluminium gallium arsenide or aluminium indium gallium phosphide are provided.

Abstract: PURPOSE: To improve the evaporation efficiency of a raw material by mounting an element of a porous sintered metal having the pore size smaller than the size of the solid raw material to a port for introducing a carrier gas into a bubbler vessel.

Abstract: A method and apparatus for the bulk delivery of a precursor, such as an organometallic compound, from a bulk container, such as a bubbler (1) to a plurality of reactor sites (12, 14, 16, 18, 20) wherein a carrier gas (2) is introduced into the container (1) of the precursor to pick up the precursor to form a gaseous mixture. The gaseous mixture is then selectively distributed to one or more of a plurality of reactor sites (12, 14, 16, 18, 20). The gaseous mixture may be stored in a reservoir (9) and be drawn by means of a pressure differential or under vacuum to each of the reactor sites, when required.