A method of forming a multijunction solar cell that includes an InGaAs buffer layer and an InGaAlAs grading interlayer disposed below, and adjacent to, the InGaAs buffer layer. The grading interlayer achieves a transition in lattice constant from one solar subcell to another adjacent solar subcell.

Radiation detecting-structures and fabrications methods thereof are presented. The methods include, for instance: providing a substrate, the substrate including at least one trench extending into the substrate from an upper surface thereof; and epitaxially forming a radiation-responsive semiconductor material layer from one or more sidewalls of the at least one trench of the substrate, the radiation-responsive semiconductor material layer responding to incident radiation by generating charge carriers therein. In one embodiment, the sidewalls of the at least one trench of the substrate include a (111) surface of the substrate, which facilitates epitaxially forming the radiation-responsive semiconductor material layer. In another embodiment, the radiation-responsive semiconductor material layer includes hexagonal boron nitride, and the epitaxially forming includes providing the hexagonal boron nitride with an a-axis aligned parallel to the sidewalls of the trench.

An epitaxially grown III-V layer is separated from the growth substrate. The III-V layer can be an inverted lattice matched (ILM) or inverted metamorphic (IMM) solar cell, or a light emitting diode (LED). A sacrificial epitaxial layer is embedded between the GaAs wafer and the III-V layer. The sacrificial layer is damaged by absorbing IR laser radiation. A laser is chosen with the right wavelength, pulse width and power. The radiation is not absorbed by either the GaAs wafer or the III-V layer. No expensive ion implantation or lateral chemical etching of a sacrificial layer is needed. The III-V layer is detached from the growth wafer by propagating a crack through the damaged layer. The active layer is transferred wafer-scale to inexpensive, flexible, organic substrate. The process allows re-using of the wafer to grow new III-V layers, resulting in savings in raw materials and grinding and etching costs.

In photonic integrated circuits implemented in silicon-on-insulator substrates, non-conductive channels formed, in accordance with various embodiments, in the silicon device layer and/or the silicon handle of the substrate in regions underneath radio-frequency transmission lines of photonic devices can provide breaks in parasitic conductive layers of the substrate, thereby reducing radio-frequency substrate losses.

A composition of matter comprising: a graphitic substrate optionally carried on a support, a seed layer having a thickness of no more than 50 nm deposited directly on top of said substrate, opposite any support; and an oxide or nitride masking layer e directly on top of said seed layer; wherein a plurality of holes are present through said seed layer and through said masking layer to C said graphitic substrate; and wherein a plurality of nanowires or nanopyramids are grown from said substrate in said holes, said nanowres or nanopyramids comprising at least one semiconducting group III-V compound.

A phototransistor includes an emitter, a collector, and a base between the emitter and the collector. The base has a thickness greater than 500 nanometers and the base absorbs photons passing through the collector to the base.

Nanostructure array optoelectronic devices are disclosed. The optoelectronic device may have one or more intermediate electrical contacts that are physically and electrically connected to sidewalls of the array of nanostructures. The contacts may allow different photo-active regions of the optoelectronic device to be independently controlled. For example, one color light may be emitted or detected independently of another using the same group of one or more nanostructures. The optoelectronic device may be a pixilated device that may serve as an LED display or imaging sensor. The pixilated device may have an array of nanostructures with alternating rows and columns of sidewall electrical contacts at different layers. A pixel may be formed at the intersection of a row contact and a column contact. As one example, a single group of one or more nanostructures has a blue sub-pixel, a green sub-pixel, and a red sub-pixel.

In photonic integrated circuits implemented in silicon-on-insulator substrates, non-conductive channels formed, in accordance with various embodiments, in the silicon device layer and/or the silicon handle of the substrate in regions underneath radio-frequency transmission lines of photonic devices can provide breaks in parasitic conductive layers of the substrate, thereby reducing radio-frequency substrate losses.

A composition of matter, in particular a photovoltaic cell, comprising: at least one core semiconductor nanowire on a graphitic substrate, said at least one core nanowire having been grown epitaxially on said substrate wherein said nanowire comprises at least one group III-V compound or at least one group II-VI compound or at least one group IV element; a semiconductor shell surrounding said core nanowire, said shell comprising at least one group III-V compound or at least one group II-VI compound or at least one group IV element such that said core nanowire and said shell form a n-type semiconductor and a p-type semiconductor respectively or vice versa; and an outer conducting coating surrounding said shell which forms an electrode contact.

Disclosed is an active photonic device having a Darlington configuration with a substrate and a collector layer that is over the substrate. The collector layer includes an inner collector region. An outer collector region substantially surrounds the inner collector region and is spaced apart from the inner collector region. A base layer is over the collector layer. A first outer base region and a second outer base region substantially surround the inner base region and are spaced apart from the inner base region and each other. An emitter layer is over the base layer. The emitter layer includes an inner emitter region that is ring-shaped and resides over and extends substantially around an outer periphery of the inner base region. A first outer emitter region and a second outer emitter region substantially surround the inner emitter region and are spaced apart from the inner emitter region and each other.