An electrode for beta-photovoltaic cells includes: a substrate formed of a conductive layer with a thickness ranging between about 10 nm to 1 micron; a composite layer of radioluminescent phosphor with radioisotope particles homogeneously dispersed therein formed on conductive substrate with a thickness ranging between about 1 and 25 microns; and a semiconductor comprising a P-i-N/P-u-N junction or a N-i-P-P junction. The radioisotope may be a beta-emitter, such as Ni-63, H-3, Pm-147, or Sr-90/Y-90.

Provided is an AlGaN unipolar carrier solar-blind ultraviolet detector that is based on the AlGaN polarization effect and that uses the double heterojunction of the p-AlzGa1-zN/i-AlyGa1-yN/n-AlxGa1-xN (0.45=<x,z<y) as the main structure of the detector. It makes full use of the polarization built-in electric field pointing from n-type AlGaN to p-type AlGaN to enhance the electric field strength of the i-type absorption region and enhance the efficiency of carrier absorption and separation. At the same time, the valence band step of the p-AlzGa1-zN/i-AlyGa1-yN heterojunction is used to effectively restrict holes from entering the absorption region to recombine with electrons, thereby increasing the carrier lifetime. Furthermore, during device manufacturing the structure is such designed that makes it difficult for photo-generated holes to participate in the photoconductivity so as to realize unipolar conduction of electrons, thereby obtaining a high response speed and high gain current.

A photovoltaic device includes an organic semiconductor and an inorganic semiconductor. The organic semiconductor includes a photoactive region that generates excitons. The inorganic semiconductor has piezoelectricity and includes a dissociation region for dissociating carriers included in the excitons. A relationship of energy levels between the photoactive region and the dissociation region satisfies at least one equation E.sub.LUMO>E.sub.C or equation E.sub.HOMO<E.sub.V.

A transceiver assembly for a wireless power transfer system includes a transceiver system comprising a photodiode assembly, a voltage converter and a light emitting diode and a photodiode. The photodiode assembly may be configured to receive a high-power laser beam from a transmitter and to convert the high-power laser beam to electrical energy. The voltage converter may be configured to adjust an input impedance based on a voltage measure of the photodiode assembly so as to maximize power transfer from the photodiode assembly to an energy storage device electrically coupled to the voltage converter. The light emitting diode and the photodiode may be configured to enable free space optical communication with the transmitter. The light emitting diode may emit signals indicating a presence and a location of the transceiver to the transmitter at least when the energy storage device requires a charge.

Optoelectronic devices having GaInNAsSb, GaInNAsBi or GaInNAsSbBi active layers are disclosed. The optoelectronic devices have an active or absorbing layer, with a bandgap within a range from 0.7 eV and 1.2 eV. The active layer is coupled to a multiplication layer. The multiplication layer is designed to provide a large optical gain with a high signal-to-noise ratio at low light levels at wavelengths up to 1.8 μm.

An electrophoretic deposition (EPD) process forms a radioluminescent phosphor and radioisotope composite layer on a conductive surface of a substrate. In the composite layer formed, the particles of radioisotope are homogeneously dispersed with the radioluminescent phosphor. The radioisotope may be a beta-emitter, such as Ni-63, H-3, Pm-147, or Sr-90/Y-90. By applying the composite layer using the EPD process, the electrode can be configured for betavoltaic, beta-photovoltaic and photovoltaic cells according to further embodiments. A direct bandgap semiconductor device can convert betas and/or photons emitted from composite layer. Methods and choice of materials and components produces a hybrid radioisotope battery, conversion of photons and nuclear decay products, or radioluminescent surfaces.

A UV sensor includes a GaN stack including a low-resistance GaN layer formed over a nucleation layer, and a high-resistance GaN layer formed over the low-resistance GaN layer, wherein a 2DEG conductive channel exists at the upper surface of the high-resistance GaN layer. An AlGaN layer is formed over the upper surface of the high-resistance GaN layer. A source contact and a drain contact extend through the AlGaN layer and contact the upper surface of the high-resistance GaN layer (and are thereby electrically coupled to the 2DEG channel). A drain depletion region extends entirely from the upper surface of the high-resistance GaN layer to the low-resistance GaN layer under the drain contact. An electrical current between the source and drain contacts is a function of UV light received by the GaN stack. An electrode is connected to the low-resistance GaN layer to allow for electrical refresh of the UV sensor.

Semiconductor optoelectronic devices having a dilute nitride active region and at least one graded or stepped interface layer between the dilute nitride active region and an adjacent higher bandgap semiconductor layer, such as a cladding layer are disclosed. In particular, the semiconductor devices have a dilute nitride active region with at least one bandgap within a range from 0.7 eV and 1.4 eV. Photodetectors comprising a dilute nitride active region with at least one graded or stepped interface layer have a higher carrier collection efficiency and a reduced dark current when compared to photodetectors comprising a dilute nitride active region without a graded or stepped interface layer.

The optoelectronic device includes a matrix of optoelectronic components including semiconductor optical amplifiers SOAs, the semiconductor optical amplifiers SOAs containing an active layer of gallium nitride GaN having multiple InGaN/GaAsN or InGaN/AlGaN quantum wells on a substrate of p-doped gallium nitride and covered with a layer of n-doped gallium nitride. The p-doped gallium nitride GaN substrate forms a column of p-GaN covered with a layer of an insulator in biocompatible material. The device can include a matrix having multiple electronic components of different heights. The optoelectronic component can be a photodiode or a semiconductor optical amplifier SOA. This optoelectronic device can be used in epiretinal or subretinal prostheses. A single epiretinal or subretinal prosthesis can include a matrix of photodiodes and a matrix of semiconductor optical amplifiers SOAs.

An ultraviolet ray detecting device is provided. The ultraviolet ray detecting device comprises: a substrate; a buffer layer disposed on the substrate; a light absorption layer disposed on the buffer layer; a capping layer disposed on the light absorption layer; and a Schottky layer disposed on a partial region of the capping layer, wherein the capping layer has an energy bandgap larger than that of the light absorption layer.