In accordance with an embodiment, a diode comprises a substrate, a dielectric material including an opening that exposes a portion of the substrate, the opening having an aspect ratio of at least 1, a bottom diode material including a lower region disposed at least partly in the opening and an upper region extending above the opening, the bottom diode material comprising a semiconductor material that is lattice mismatched to the substrate, a top diode material proximate the upper region of the bottom diode material, and an active diode region between the top and bottom diode materials, the active diode region including a surface extending away from the top surface of the substrate.

An electrical device that includes a first semiconductor device positioned on a first portion of a substrate and a second semiconductor device positioned on a third portion of the substrate, wherein the first and third portions of the substrate are separated by a second portion of the substrate. An interlevel dielectric layer is present on the first, second and third portions of the substrate. The interlevel dielectric layer is present over the first and second semiconductor devices. An optical interconnect is positioned over the second portion of the semiconductor substrate. At least one material layer of the optical interconnect includes an epitaxial material that is in direct contact with a seed surface within the second portion of the substrate through a via extending through the least one interlevel dielectric layer.

A quantum well infrared photodetector (QWIP) and method of making is disclosed. The QWIP includes a plurality of epi-layers formed into multiple periods of quantum wells, each of the quantum wells being separated by a barrier, the quantum wells and barriers being formed of II-VI semiconductor materials. A multiple wavelength QWIP is also disclosed and includes a plurality of QWIPs stacked onto a single epitaxial structure, in which the different QWIPs are designed to respond at different wavelengths. A dual wavelength QWIP is also disclosed and includes two QWIPs stacked onto a single epitaxial structure, in which one QWIP is designed to respond at 10 m and the other at 3-5 m wavelengths.

A method is provided for making smooth crystalline semiconductor thin-films and hole and electron transport films for solar cells and other electronic devices. Such semiconductor films have an average roughness of 3.4 nm thus allowing for effective deposition of additional semiconductor film layers such as perovskites for tandem solar cell structures which require extremely smooth surfaces for high quality device fabrication.

The present invention presents a process for preparing a quantum dot array comprising at least the steps of: (a) providing a crystalline semiconductor substrate surface; (b) depositing quantum dots on the said substrate surface by a process of successive ionic layer adsorption and reaction (SILAR). The steps can be repeated to build up a quantum dot superlattice structure.

Disclosed are methods and systems for forming a layer on a web with reduced levels of particulates. The layer is formed from a fluid mixture(s) or solution of chemical reagents that react to form the layer. The system includes a conveyor device provided configured to carry the web within the chamber while the first surface of the web undergoes one or more processing steps; a first fluid delivery apparatus and a second fluid delivery apparatus, and a first fluid removal apparatus. The first fluid removal apparatus is positioned within a space arranged between the first and the second delivery apparatuses.

This disclosure provides systems, methods, and apparatus related to photodetectors. In one aspect, a photodetector device comprises a substrate, a polycrystalline layer disposed on the substrate, and a first electrode and a second electrode disposed on the polycrystalline layer. The polycrystalline layer comprises nanograins with grain boundaries between the nanograins. The nanograins comprise a semiconductor material. A doping element comprising a halogen is segregated at the grain boundaries. A length of the polycrystalline layer is between and separating the first electrode and the second electrode.

A method is provided for fabricating a thin-film semiconductor device. The method includes providing a plurality of raw semiconductor materials. The raw semiconductor materials undergo a pre-reacting process to form a homogeneous compound semiconductor material. This pre-reaction typically includes processing above the liquidus temperature of the compound semiconductor. The compound semiconductor material is reduced to a particulate form and deposited onto a substrate to form a thin-film having a composition and atomic structure substantially the same as a composition and atomic structure of the compound semiconductor material.

Improved methods and apparatus for forming thin film layers of chalcogenide on a substrate web. According to the present teachings, a feedback control system may be employed to measure one or more properties of the web and/or the chalcogenide layer, and to adjust one or more parameters of the system or buffer layer deposition method in response to the measurement.

An electro-optical device can include a plurality of nanocrystals positioned between a first electrode and a second electrode.