A gas-sensing element includes a gas-sensing surface of transition metal-doped metal oxide semiconductor of a first metal (particularly tin oxide) over a body of the metal oxide semiconductor. The gas-sensing element includes an auxiliary component of: (1) internally-disposed second metal (particularly copper, gold or silver) disposed in the gas-sensing element between the body and the gas-sensing surface, or (2) a metal chalcogenide (particularly sulfide or sulphide) disposed at the gas-sensing surface or internally disposed in the gas-sensing element between the body and the gas-sensing surface that stabilizes the second metal at the gas-sensing surface.

A photovoltaic device is presented. The photovoltaic device includes a layer stack; and an absorber layer is disposed on the layer stack. The absorber layer comprises selenium, wherein an atomic concentration of selenium varies across a thickness of the absorber layer. The photovoltaic device is substantially free of a cadmium sulfide layer.

A chalcogenide film is provided. The chalcogenide film includes a noble metal chalcogenide material having a formula MC.sub.x. M represents a noble metal. C represents a chalcogen. x is any one positive value equal to or more than 1.4 and less than 2. The chalcogenide film is configured to generate electrons and holes upon light incident on the chalcogenide film.

Techniques for precisely controlling the composition of volatile components (such as sulfur (S), selenium (Se), and tin (Sn)) of chalcogenide semiconductors in real-timeduring production of the material are provided. In one aspect, a method for forming a chalcogenide semiconductor material includes providing a S source(s) and a Se source(s); heating the S source(s) to form a S-containing vapor; heating the Se source(s) to form a Se-containing vapor; passing a carrier gas first through the S-containing vapor and then through the Se-containing vapor, wherein the S-containing vapor and the Se-containing vapor are transported via the carrier gas to a sample; and contacting the S-containing vapor and the Se-containing vapor with the sample under conditions sufficient to form the chalcogenide semiconductor material. A multi-chamber processing apparatus is also provided.

Distributor assemblies for vapor transport deposition systems, and methods of conducting vapor transport deposition, are described.

A method for depositing a CdTe layer on a substrate in a vacuum chamber by means of physical gas phase deposition is provided. The substrate is heated to a coating temperature before the deposition process and then guided past a vessel in which CdTe is converted into a vapour state, a gaseous component with an increased pressure (compared to the vacuum in the vacuum chamber) flowing through at least one inlet, against the substrate surface to be coated, such that the gaseous component is adsorbed on the substrate surface to be coated before the substrate is guided past the at least one vessel.

Disclosed is a method of providing a constant concentration of a metal-containing precursor compound in the vapor phase in a carrier gas. Such method is particularly useful in supplying a constant concentration of a gaseous metal-containing compound to a plurality of vapor deposition reactors.

Systems and methods for growing high-quality CdTe-based materials at high growth rates are provided. According to an aspect of the invention, a method includes depositing a first CdTe-based layer on a CdTe-based template at a rate of greater than 1 m/min. Each of the first CdTe-based layer and the CdTe-based template has a single-crystal structure and/or a large-grain polycrystalline structure. The depositing is performed by physical vapor deposition.

A vapor transport deposition system and method that includes a vaporizer and distributor unit and at least one auxiliary process unit for integrating thin-film layer deposition with one or more pre- or post-deposition processes.

An optical phase difference component includes a transparent base with a concave-convex pattern having concave portions and convex portions; a coating layer coating the concave portions and the convex portions of the concave-convex pattern; a gap defined between the convex portions of the concave-convex pattern coated with the coating layer; and a closing layer provided on the concave-convex pattern to connect tops of the convex portions of the concave-convex pattern and to close the gap. A refractive index n.sub.1 of each of the convex portions and a refractive index n.sub.2 of the coating layer at a wavelength of 550 nm satisfy n.sub.2n.sub.10.8. The optical phase difference component has a phase difference property of reverse dispersion and a wide viewing angle.