Kesterite photovoltaic devices having a back surface field layer are provided. In one aspect, a method of forming a photovoltaic device includes: forming a complete photovoltaic device having a substrate, an electrically conductive layer on the substrate, an absorber layer on the electrically conductive layer, a buffer layer on the absorber layer, and a transparent front contact on the buffer layer; removing the substrate and the electrically conductive layer from the complete photovoltaic device to expose a backside surface of the absorber layer; forming a passivating layer on the backside surface of the absorber layer; and forming a high work function back contact on the passivating layer. A photovoltaic device having a passivating layer is also provided.

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.

A photodetector includes an insulating layer on a substrate, a first graphene layer on the insulating layer, a 2-dimensional (2D) material layer on the first graphene layer, a second graphene layer on the 2D material layer, a first electrode on the first graphene layer, and a second electrode on the second graphene layer. The 2D material layer includes a barrier layer and a light absorption layer. The barrier layer has a larger bandgap than the light absorption layer.

Techniques for increasing grain size in AZTSSe absorber materials are provided. In one aspect, a method for forming an absorber film on a substrate includes: contacting the substrate with an Ag source, a Zn source, a Sn source, and an S source and/or an Se source under conditions sufficient to form the absorber film on the substrate having a target composition of: Ag.sub.XZn.sub.YSn(S,Se).sub.Z, wherein 1.7<x<2.2, 0.9<y<1.3, and 3.5<z<4.5, and including an amount of the Ag source that is from about 10% to about 30% greater than is needed to achieve the target composition; annealing the absorber film; and removing excess Ag from the absorber film. A solar cell and method for fabrication thereof are also provided.

A photovoltaic device and method include a substrate, a conductive layer formed on the substrate and an absorber layer formed on the conductive layer from a CuZnSn containing chalcogenide material. An emitter layer is formed on the absorber layer and a buffer layer is formed on the emitter layer including an atomic layer deposition (ALD) layer. A transparent conductor layer is formed on the buffer layer.

A photovoltaic device and method include a substrate, a conductive layer formed on the substrate and an absorber layer formed on the conductive layer from a CuZnSn containing chalcogenide material. An emitter layer is formed on the absorber layer and a buffer layer is formed on the emitter layer including an atomic layer deposition (ALD) layer. A transparent conductor layer is formed on the buffer layer.

In various embodiments, evaporation sources for deposition systems are heated and/or cooled via a fluid-based thermal management system.

A method of making a CZTS/inorganic thin-film tandem solar cell including depositing a textured buffer layer on a substrate, depositing a metal-inorganic film from a eutectic alloy on the buffer layer, and depositing additional elements in CZTS forming a CZTS layer based on the metal from the metal-inorganic film, the metal being incorporated into the CZTS film.

A simple manufacturing method is provided for the fabrication of the IV-VI group of semiconductor films on inexpensive substrates for highly efficient tandem or multi junction solar cells and a variety of other electronic devices such as transistors and LEDs. Specifically, the method includes depositing a textured oxide buffer on a substrate; depositing a metal-inorganic film from a eutectic alloy on the buffer layer, the metal being a component of a IV-VI compound; and forming a layer on the metal-inorganic film on which an additional element from the IV-VI compound is added, forming a IV-VI layer on a semiconductor device. The films comprising tin sulfidesSnS (tin sulphide), SnS.sub.2, and SnS.sub.3are grown on inexpensive substrates, such as glass or flexible plastic, at low temperature, allowing for R2R (roll-to-roll) processing.

The present invention provides a heat treatment method, particularly a heat treatment method in which a protective layer is directly applied onto a precursor to ensure that the precursor on each portion of the substrate is treated based on substantially the same conditions so that the quality of the prepared product layer is improved. The method of the present invention comprises: (1) providing a substrate; (2) applying a precursor onto the surface of the substrate; (3) covering the precursor-applied substrate with a protective layer to bring the substrate and the protective layer into direct contact; (4) placing the substrate obtained from step (3) into a heat chamber for heat treatment; and (5) removing the protective layer. A product prepared by said heat treatment method is also provided.