Provided are structures and methods for doping polycrystalline thin film semiconductor materials in photovoltaic devices. Embodiments include methods for forming and treating a photovoltaic semiconductor absorber layer.

A doped photovoltaic device is presented. The photovoltaic device includes a semiconductor absorber layer or stack disposed between a front contact and a back contact. The absorber layer comprises cadmium, selenium, and tellurium doped with Ag, and optionally with Cu. The Ag dopant may be added to the absorber in amounts ranging from 510.sup.15/cm.sup.3 to 2.510.sup.17/cm.sup.3 via any of several methods of application before, during, or after deposition of the absorber layer. The photovoltaic device has improved Fill Factor and P.sub.MAX at higher P.sub.r (=I.sub.sc*V.sub.oc product) values, e.g. about 160 W, which results in improved conversion efficiency compared to a device not doped with Ag. Improved PT may result from increased I.sub.sc, increased V.sub.oc, or both.

The present disclosure relates to thin-film solar cells with improved efficiency and methods for producing thin-film solar cells having increased efficiency. In certain embodiments, thin-film solar cells having an efficiency of over 21%, over 20%, over 19%, over 15%, over 10%, etc. has been obtained using the methods of the disclosure. In certain aspects, the methods of the disclosure use passivation, passivating oxides, and/or doping treatments in increase the efficiency of the thin-film solar cells; e.g., CdTe-based thin-film solar cells.

Provided is a stable CdZnTe monocrystalline substrate having a small leakage current even when a high voltage is applied and having a lower variation in resistivity with respect to variations in applied voltage values. A semiconductor wafer comprising a cadmium zinc telluride monocrystal having a zinc concentration of 4.0 at % or more and 6.5 at % or less and a chlorine concentration of 0.1 ppm by mass or more and 5.0 ppm by mass or less, wherein the semiconductor wafer has a resistivity of 1.0?10.sup.7 ?cm or more and 1.0?10.sup.8 ?cm or less when a voltage of 900 V is applied, and wherein a ratio (variation ratio) of the resistivity at application of 0 V to the resistivity at application of a voltage of 900 V is 20% or less.

A detector that includes an all-oxide, Schottky-type heterojunction. The metal side of the heterojunction is formed, for example, from a dysprosium (Dy) doped cadmium oxide (CdO) (i.e., CdO:Dy). The semiconductor side of the heterojunction is formed, for example, from cadmium magnesium oxide (CdMgO). On the metal side of the junction, hot electrons are created through the excitation of surface plasmon polaritons by infrared radiation. The hot electrons are able to cross the Schottky-type barrier of the heterojunction into the conduction band of the semiconductor where they can be detected. The working wavelength of infrared radiation that is being detected can be adjusted or tuned by modifying the Dy content of Dy-doped CdO. The height of the Schottky-type barrier can also be adjusted by modifying the composition of CdMgO, which allows for the optimization of the Schottky-type barrier height for a given working wavelength.

A photovoltaic cell can include a dopant in contact with a semiconductor layer.

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.

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.

A photovoltaic cell can include a dopant in contact with a semiconductor layer.

Photodetectors based on colloidal quantum dots and methods of making the photodetectors are provided. Also provided are methods for doping films of colloidal quantum dots via a solid-state cation exchange method. The photodetectors include multi-band photodetectors composed of two or more rectifying photodiodes stacked in aback-to-back configuration. The doping methods rely on a solid-state cation exchange that employs sacrificial semiconductor nanoparticles as a dopant source for a film of colloidal quantum dots.