Refractive optical element designs are provided for high geometric optical efficiency over a wide range of incident angles. To minimize Fresnel reflection losses, the refractive optical element designs employ multiple encapsulant materials, differing in refractive index. Concentrator photovoltaic subassemblies are formed by embedding a high efficiency photovoltaic device within the refractive optical element, along with appropriate electrical contacts and heat sinks. Increased solar electric power output is obtained by employing a single-junction III-V material structure with light-trapping structures.

An optoelectronic semiconductor structure (SC) comprises an active InGaN-based layer disposed between an n-type injection layer and a p-type injection layer, the active p-type injection layer comprising a first InGaN layer and, disposed on the first layer, a second layer composed of a plurality of Al—GaInN elemental layers, each elemental layer having a thickness less than its critical relaxation thickness, two successive elemental layers having different aluminum and/or indium and/or gallium compositions.

Provided are methods for obtaining n-type doped metal chalcogenide quantum dot solid-state films. In some embodiments, the methods include forming an metal chalcogenide quantum dot solid-state film, carrying out a n-doping process on the metal chalcogenide quantum dots of the metal chalcogenide quantum dot solid-state film so that they exhibit intraband absorption, wherein the process includes partially substituting chalcogen atoms by halogen atoms in the metal chalcogenide quantum dots and providing a substance on the plurality of metal chalcogenide quantum dots, to avoid oxygen p-doping of the metal chalcogenide quantum dots. Also provided are optoelectronic devices, which in some embodiments can include an n-type doped metal chalcogenide quantum dot solid-state film (A) obtained by a method as disclosed herein and first (E1) and second (E2) electrodes in physical contact with two respective distanced regions of the film (A).

A photo detector includes a superlattice with an undoped first semiconductor layer including undoped intrinsic semiconductor material, a doped second semiconductor layer having a first conductivity type on the first semiconductor layer, an undoped third semiconductor layer including undoped intrinsic semiconductor material on the second semiconductor layer, and a fourth semiconductor layer having a second opposite conductivity type on the third semiconductor layer, along with a first contact having the first conductivity type in the first, second, third, and fourth semiconductor layers, and a second contact having the second conductivity type and spaced apart from the first contact in the first, second, third, and fourth semiconductor layers. An optical shield on a second shielded portion of a top surface of the fourth semiconductor layer establishes electron and hole lakes. A packaging structure includes an opening that allows light to enter an exposed first portion of the top surface of the fourth semiconductor layer.

Techniques are disclosed for facilitating detection of electromagnetic radiation using superlattice-based detector systems and methods. In one example, an infrared detector includes a first superlattice structure including first periods. Each of the first periods includes a first sub-layer and a second sub-layer adjacent to the first sub-layer. The first and second sub-layers include first and second semiconductor materials. The infrared detector further includes a second superlattice structure disposed on the first superlattice structure. The second superlattice structure includes second periods. Each of the second periods includes a third sub-layer and a fourth sub-layer adjacent to the third sub-layer. The third-sub-layer includes a third semiconductor material. The fourth sub-layer includes a fourth semiconductor material. A p-n junction is formed at an interface within the second superlattice structure or at an interface between the first and second superlattice structures.

Heterostructures containing one or more sheets of positive charge, or alternately stacked AlGaN barriers and AlGaN wells with specified thickness are provided. Also provided are multiple quantum well structures and p-type contacts. The heterostructures, the multiple quantum well structures and the p-type contacts can be used in light emitting devices and photodetectors.

The invention relates inter alia to a photoconductor (10) comprising a multilayer (13) which comprises a plurality of photoconductive semiconductor layers (131-134). According to the invention, the multilayer (13) comprises at least two sublayers (130) which each comprise at least a first photoconductive semiconductor layer (131) and a second photoconductive semiconductor layer (132), wherein the first and the second photoconductive semiconductor layer (131, 132) are doped to different degrees for each of the sublayers (130).

The present invention relates to techniques, including methods and devices, for optical technology. In particular, the present invention provides methods, devices, and structures for optical devices, and in particular, photo diodes, commonly called photo sensors.

A photo detector includes a superlattice with an undoped first semiconductor layer including undoped intrinsic semiconductor material, a doped second semiconductor layer having a first conductivity type on the first semiconductor layer, an undoped third semiconductor layer including undoped intrinsic semiconductor material on the second semiconductor layer, and a fourth semiconductor layer having a second opposite conductivity type on the third semiconductor layer, along with a first contact having the first conductivity type in the first, second, third, and fourth semiconductor layers, and a second contact having the second conductivity type and spaced apart from the first contact in the first, second, third, and fourth semiconductor layers. An optical shield on a second shielded portion of a top surface of the fourth semiconductor layer establishes electron and hole lakes. A packaging structure includes an opening that allows light to enter an exposed first portion of the top surface of the fourth semiconductor layer.

An infrared detector includes a pixel separation wall. The infrared detector includes a semiconductor crystal substrate; a first contact layer formed on the semiconductor crystal substrate, a pixel separation wall formed on the first contact layer and configured to separate pixels; a buffer layer formed on the first contact layer and on a side surface of the pixel separation wall in a region surrounded by the pixel separation wall, an infrared-absorbing layer formed on the buffer layer, a second contact layer formed on the infrared-absorbing layer, an upper electrode formed on the second contact layer, and a lower electrode formed on the first contact layer. The buffer layer and the first contact layer are formed of a compound semiconductor of a first conductivity type. The pixel separation wall and the second contact layer are formed of a compound semiconductor of a second conductivity type.