A solar cell includes a light-absorbing layer, comprising a Cu compound or Cd compound, between two electrodes facing each other, has an impurity material layer, comprising an impurity element to be provided to the Cu compound or Cd compound, formed on any one side or both sides between the two electrodes and the light absorbing layer, and has a doping layer formed on one part of the light absorbing layer by means of the impurity element being diffused on the light absorbing layer.

A photovoltaic device includes a substrate, a first electrode formed on the substrate and a p-type absorber layer including a chalcogenide compound. An n-type layer includes a zinc oxysulfide material having a sulfur content adjusted to match a feature of the absorber layer. A transparent contact is formed on the n-type layer.

A semiconductor nanoparticle dispersion is provided. The semiconductor nanoparticle including a plurality of semiconductor nanoparticles having a radius equal to or larger than an exciton Bohr radius; and a solvent dispersed with the plurality of semiconductor nanoparticles.

Various embodiments of a semiconductor device and related fabrication methods are disclosed. In one exemplary embodiment, the semiconductor device may include a substrate and a plurality of two-dimensional semiconductor films over the substrate, where a photogain of the two-dimensional films is above about 10.sup.3 when measured at room temperature. In another exemplary embodiment, a semiconductor device may comprise a substrate comprising nanorods or nanodots and a plurality of two-dimensional films disposed on the substrate.

According to the embodiments provided herein, a photovoltaic device can include a buffer layer adjacent to an absorber layer doped p-type with a group V dopant. The buffer layer can have a plurality of layers compatible with group V dopants.

The present invention provides a radiation detection system for detecting X-ray and gamma rays featuring Cd.sub.1-xMg.sub.xTe in solid solution as a crystal semiconductor and electrical connection means. The crystal has a composition in the range of Cd.sub.0.99Mg.sub.0.01Te to Cd.sub.0.71Mg.sub.0.29Te and may be doped with indium or another Group III element, which may be suitable for use at room temperature as well as controlled temperatures. The present invention further provides a method for detecting X- or gamma ray radiation by (a) providing a solid solution Cd.sub.1-xMg.sub.xTe crystal in the composition range of Cd.sub.0.99Mg.sub.0.01Te to Cd.sub.0.71Mg.sub.0.29Te; (b) providing an electrical contact means for connecting the Cd.sub.1-xMg.sub.xTe crystal to an amplification, measurement, identification or imaging means; and (c) detecting the presence of the X- or gamma ray radiation.

A semiconductor nanoparticle dispersion is provided. The semiconductor nanoparticle including a plurality of semiconductor nanoparticles having a radius equal to or larger than an exciton Bohr radius; and a solvent dispersed with the plurality of semiconductor nanoparticles.

This disclosure provides systems, methods, and apparatus related to a hybrid photo-electrochemical and photo-voltaic cell. In one aspect, device includes a substrate comprising a semiconductor, a transparent conductor disposed on the second surface of the substrate, a photoanode disposed on the transparent conductor, an electrolyte in electrical communication with the photoanode, and an electrode in contact with the electrolyte. The substrate is doped with a first n-type dopant. A first area of a first surface of the substrate is heavily doped with a first p-type dopant. A second area of the first surface of the substrate is heavily doped with a second n-type dopant. The second surface of the substrate is heavily doped with a second p-type dopant. The electrode is in electrical contact with the second area. The first area is in electrical contact with the second area through an electrical load.

The present invention proposes a method to form a double-graded CdSeTe thin film. The method comprises providing a base substrate, forming a first CdSe.sub.wTe.sub.1-w layer having a first amount w1 of selenium in it, forming a second CdSe.sub.wTe.sub.1-w layer having a second amount w2 of selenium in it and forming a third CdSe.sub.wTe.sub.1-w layer having a third amount w3 of selenium in it. The second amount w2 lies in the range between 0.25 and 0.4, whereas each of the amounts w1 and w3 lies in the range extending from 0 to 1. According to the present invention, the energy gap in the first and the third CdSe.sub.wTe.sub.1-w layers is equal to or higher than 1.45 eV and the energy gap in the second CdSe.sub.wTe.sub.1-w layer lies in the range between 1.38 eV and 1.45 eV and is smaller than the energy gap in the first and the third CdSe.sub.wTe.sub.1-w layers.

The present invention proposes a method to produce thin film CdTe solar cells having a pin-hole free and uniformly doped CdTe layer with a reduced layer thickness. The method according to the present invention is an efficient way to prevent shunting of the solar cells, to improve reliability and long-term stability of the solar cells and to provide a uniform doping of the CdTe layer. This is achieved by applying a sacrificial doping layer between a first CdTe layer having large grains and a second CdTe layer having small grains, which together form the CdTe layer of the solar cells. Furthermore it provides the possibility to eliminate the CdCl.sub.2 activation treatment step in case the sacrificial doping layer comprises a halogen.