A method of forming a semiconductor structure includes forming an opening in a dielectric layer, forming a recess in an exposed part of a substrate, and forming a lattice-mismatched crystalline semiconductor material in the recess and opening.

An engineered substrate comprising: a seed layer made of a first semiconductor material for growth of a solar cell; a first bonding layer on the seed layer; a support substrate made of a second semiconductor material; a second bonding layer on a first side of the support substrate; a bonding interface between the first and second bonding layers; the first and second bonding layers each made of metallic material; wherein doping concentration and thickness of the engineered substrate, in particular, of the seed layer, the support substrate, and both the first and second bonding layers, are selected such that the absorption of the seed layer is less than 20%, preferably less than 10%, as well as total area-normalized series resistance of the engineered substrate is less than 10 mOhm.Math.cm.sup.2, preferably less than 5 mOhm.Math.cm.sup.2.

An engineered substrate comprising: a seed layer made of a first semiconductor material for growth of a solar cell; a first bonding layer on the seed layer; a support substrate made of a second semiconductor material; a second bonding layer on a first side of the support substrate; a bonding interface between the first and second bonding layers; the first and second bonding layers each made of metallic material; wherein doping concentration and thickness of the engineered substrate, in particular, of the seed layer, the support substrate, and both the first and second bonding layers, are selected such that the absorption of the seed layer is less than 20%, preferably less than 10%, as well as total area-normalized series resistance of the engineered substrate is less than 10 mOhm.Math.cm.sup.2, preferably less than 5 mOhm.Math.cm.sup.2.

Thin freestanding nitride veneers can be used for the fabrication of semiconductor devices. These veneers are typically less than 100 microns thick. The use of thin veneers also eliminates the need for subsequent wafer thinning for improved thermal performance and 3D packaging.

Thin freestanding nitride veneers can be used for the fabrication of semiconductor devices. These veneers are typically less than 100 microns thick. The use of thin veneers also eliminates the need for subsequent wafer thinning for improved thermal performance and 3D packaging.

A semiconductor nanowire device includes at least one semiconductor nanowire having a bottom surface and a top surface, an insulating material which surrounds the semiconductor nanowire, and an electrode ohmically contacting the top surface of the semiconductor nanowire. A contact of the electrode to the semiconductor material of the semiconductor nanowire is dominated by the contact to the top surface of the semiconductor nanowire.

A semiconductor nanowire device includes at least one semiconductor nanowire having a bottom surface and a top surface, an insulating material which surrounds the semiconductor nanowire, and an electrode ohmically contacting the top surface of the semiconductor nanowire. A contact of the electrode to the semiconductor material of the semiconductor nanowire is dominated by the contact to the top surface of the semiconductor nanowire.

An optical transducer system that has a light source and a transducer. The light source generates light that has a predetermined photon energy. The transducer has a bandgap energy that is smaller than the photon energy. An increased optical to electrical conversion efficiency is obtained by illuminating the transducer at increased optical power densities. A method of converting optical energy to electrical energy is also provided.

An optical transducer system that has a light source and a transducer. The light source generates light that has a predetermined photon energy. The transducer has a bandgap energy that is smaller than the photon energy. An increased optical to electrical conversion efficiency is obtained by illuminating the transducer at increased optical power densities. A method of converting optical energy to electrical energy is also provided.

Provided is an energy harvesting device, including a solar cell including at least one active layer for receiving a first range of electromagnetic frequencies, at least one layer including antenna structures for receiving RF energy and formed on a first side of the solar cell, and at least one semiconductor for absorbing IR energy, and formed on a second side of the solar cell opposite the first side.