Abstract: Methods and compositions for the surface cleaning and passivation of CdTe substrates usable in solar cells are disclosed. In some embodiments amine-containing chelators are used and in other embodiments phosphorus-containing chelators are used.

Abstract: In some embodiments, oxidants such as ozone (O3) and/or nitrous oxide (N2O) are used during the reactive sputtering of metal-based semiconductor layers used in TFT devices. The O3 and N2O gases are stronger oxidants and result in a decrease in the concentration of oxygen vacancies within the metal-based semiconductor layer. The decrease in the concentration of oxygen vacancies may result in improved stability under conditions of negative bias illumination stress (NBIS).

Abstract: Optical absorbers, solar cells comprising the absorbers, and methods for making the absorbers are disclosed. The optical absorber comprises a semiconductor layer having a bandgap of between about 1.0 eV and about 1.6 eV disposed on a substrate, wherein the semiconductor comprises two or more earth abundant elements. The bandgap of the optical absorber is graded through the thickness of the layer by partial substitution of at least one grading element from the same group in the periodic table as the at least one of the two or more earth abundant elements.

Abstract: A gradient in the composition of at least one of the elements of a metal-based semiconductor layer is introduced as a function of depth through the layer. The gradient(s) influence the current density response of the device at different gate voltages. In some embodiments, the composition of an element (e.g. Ga) is greater at the interface between the metal-based semiconductor layer and the source/drain layers. The shape of the gradient profile is one of linear, stepped, parabolic, exponential, and the like.

Abstract: Methods of forming absorber layers in a TFPV device are provided. Methods are described to provide the formation of metal oxide films and heating the metal oxide films in the presence of a chalcogen to form a metal-oxygen-chalcogen alloy. Methods are described to provide the formation of metal oxide films, forming a layer of elemental chalcogen on the metal oxide film, and heating the stack to form a metal-oxygen-chalcogen alloy. In some embodiments, the metal oxide film includes zinc oxide and the chalcogen includes selenium.

Abstract: Optical absorbers and methods are disclosed. The methods comprise depositing a plurality of precursor layers comprising one or more of Cu, Ga, and In on a substrate, and heating the layers in a chalcogenizing atmosphere. The plurality of precursor layers can be one or more sets of layers comprising at least two layers, wherein each layer in each set of layers comprises one or more of Cu, Ga, and In exhibiting a single phase. The layers can be deposited using two or three targets selected from Ag and In containing less than 21% In by weight, Cu and Ga where the Cu and Ga target comprises less than 45% Ga by weight, Cu(In,Ga), wherein the Cu(In,Ga) target has an atomic ratio of Cu to (In+Ga) greater than 2 and an atomic ratio of Ga to (Ga+In) greater than 0.5, elemental In, elemental Cu, and In2Se3 and In2S3.

Abstract: A method for forming TFPV absorber layer. A first layer including In is formed on a substrate. The first layer is partially or fully selenized to form a layer that includes InxSey. A second layer is formed on the partially or fully selenized first layer. The second layer may include multiple layers of Cu and Cu—Ga or may be a single layer of Cu—Ga. The Cu—Ga layers can be deposited from sputtering targets wherein the Ga concentration in one or more target(s) is between about 25 atomic % and about 66 atomic %. The deposition may be performed in a batch or in-line deposition system. The first and second layers are then fully selenized to form a CIGS layer.

Abstract: Optical absorbers, solar cells comprising the optical absorbers, and methods for making the absorbers are disclosed. The optical absorber comprises a layer comprising a semiconductor having a bandgap of between about 1.0 eV and about 1.6 eV on a substrate. The thickness of the layer is from about 1 to about 10 microns. The semiconductor comprises Fe, at least one Group IVA element, and at least one Group VIA element. The Group VIA element can be S, Se or Te. The Group IVA element can be Si or Ge. Typical compositions are Fe2(Si,Ge)(S,Se)4. The bandgap can be graded through the thickness of the absorber. High Productivity Combinatorial methods can be used to optimize the composition and grading.

Abstract: A thermal processing apparatus and method in which a first laser source, for example, a CO2 emitting at 10.6 ?m is focused onto a silicon wafer as a line beam and a second laser source, for example, a GaAs laser bar emitting at 808 nm is focused onto the wafer as a larger beam surrounding the line beam. The two beams are scanned in synchronism in the direction of the narrow dimension of the line beam to create a narrow heating pulse from the line beam when activated by the larger beam. The energy of GaAs radiation is greater than the silicon bandgap energy and creates free carriers. The energy of the CO2 radiation is less than the silicon bandgap energy so silicon is otherwise transparent to it, but the long wavelength radiation is absorbed by the free carriers.

Abstract: A gallium-containing alloy is formed on the light-receiving surface of a CIGS absorber layer, and, in conjunction with a subsequent selenization or anneal process, is converted to a gallium-rich region at the light-receiving surface of the CIGS absorber layer. A second gallium-rich region is formed at the back contact surface of the CIGS absorber layer during selenization, so that the CIGS absorber layer has a double-graded gallium concentration that increases toward the light-receiving surface and toward the back contact surface of the CIGS absorber layer. The double-graded gallium concentration advantageously produces a double-graded bandgap profile for the CIGS absorber layer.

Abstract: A method for making low emissivity panels, including forming a base layer to promote a seed layer for a conductive silver layer. The base layer can be an amorphous layer or a nanocrystalline layer, which can facilitate zinc oxide seed layer growth, together with smoother surface and improved thermal stability. The base layer can include doped tin oxide, for example, tin oxide doped with Al, Ga, In, Mg, Ca, Sr, Sb, Bi, Ti, V, Y, Zr, Nb, Hf, Ta, or any combination thereof. The doped tin oxide base layer can influence the growth of (002) crystallographic orientation in zinc oxide, which in turn serves as a seed layer template for silver (111).

Abstract: In some embodiments, Cu—In—Ga precursor films are deposited by co-sputtering from multiple targets. Specifically, the co-sputtering method is used to form layers that include In. The co-sputtering reduces the tendency for the In component to agglomerate and results in smoother, more uniform films. In some embodiments, the Ga concentration in one or more target(s) is between about 25 atomic % and about 66 atomic %. The deposition may be performed in a batch or in-line deposition system. If an in-line deposition system is used, the movement of the substrates through the system may be continuous or may follow a “stop and soak” method of substrate transport.

Abstract: Methods are described for forming CIGS absorber layers in TFPV devices with graded compositions and graded band gaps. Methods are described for utilizing Al to increase the band gap at the front surface of the absorber layer. Methods are described for forming a Cu—In—Ga layer followed by partial or full selenization. This results in a higher Ga concentration at the back interface. The substrate is then exposed to an aluminum CVD precursor while the substrate is still in the selenization equipment to deposit a thin Al layer. The substrate is then exposed to a Se source to fully convert the absorber layer. This results in a higher Al concentration at the front of the absorber.

Abstract: A method for high temperature selenization of Cu—In—Ga metal precursor films comprises a partial selenization at a temperature between about 350 C and about 450 C in a Se-containing atmosphere followed by a more fully selenization step at a temperature between about 550 C and about 650 C in a Se-containing atmosphere. The Se-containing component of the atmosphere is removed through a rapid gas exchange process and the CIGS film is annealed to influence the Ga distribution throughout the depth of the film.

Abstract: Methods are described for forming CIGS absorber layers in TFPV devices with graded compositions and graded band gaps. Methods are described for utilizing Ag to increase the band gap at the front surface of the absorber layer. Methods are described for utilizing Al to increase the band gap at the front surface of the absorber layer. Methods are described for utilizing at least one of Na, Mg, K, or Ca to increase the band gap at the front surface of the absorber layer.

Abstract: Methods of forming CZTS absorber layers in a TFPV device with a graded bandgap with or without a graded concentration are provided. In general, a Cu—Zn—Sn—(S, Se) precursor film is formed by sputtering. The Cu—Zn—Sn—(S, Se) precursor film can be formed as a single layer or as a multilayer stack. The composition may be uniform or graded throughout the thickness of the film. In some embodiments, the sputtering is performed in a reactive atmosphere including a chalcogen source (e.g. H2S, H2Se, etc.). The films, in conjunction with a subsequent selenization or anneal process, are converted to an absorber layer.

Abstract: Methods are described for forming CIGS absorber layers in TFPV devices with graded compositions and graded band gaps. Methods are described for utilizing Al to increase the band gap at the front surface of the absorber layer. Methods are described for forming a Cu—In—Ga layer followed by partial or full selenization. This results in a higher Ga concentration at the back interface. The substrate is then exposed to an aluminum CVD precursor while the substrate is still in the selenization equipment to deposit a thin Al layer. The substrate is then exposed to a Se source to fully convert the absorber layer. This results in a higher Al concentration at the front of the absorber.

Abstract: A gallium-containing alloy is formed on the light-receiving surface of a CIGS absorber layer, and, in conjunction with a subsequent selenization or anneal process, is converted to a gallium-rich region at the light-receiving surface of the CIGS absorber layer. A second gallium-rich region is formed at the back contact surface of the CIGS absorber layer during selenization, so that the CIGS absorber layer has a double-graded gallium concentration that increases toward the light-receiving surface and toward the back contact surface of the CIGS absorber layer. The double-graded gallium concentration advantageously produces a double-graded bandgap profile for the CIGS absorber layer.

Abstract: A thermal processing apparatus and method in which a first laser source, for example, a CO2 emitting at 10.6 ?m is focused onto a silicon wafer as a line beam and a second laser source, for example, a GaAs laser bar emitting at 808 nm is focused onto the wafer as a larger beam surrounding the line beam. The two beams are scanned in synchronism in the direction of the narrow dimension of the line beam to create a narrow heating pulse from the line beam when activated by the larger beam. The energy of GaAs radiation is greater than the silicon bandgap energy and creates free carriers. The energy of the CO2 radiation is less than the silicon bandgap energy so silicon is otherwise transparent to it, but the long wavelength radiation is absorbed by the free carriers.

Abstract: A method for high temperature selenization of Cu—In—Ga metal precursor films comprises a partial selenization at a temperature between about 350 C and about 450 C in a Se-containing atmosphere followed by a more fully selenization step at a temperature between about 550 C and about 650 C in a Se-containing atmosphere. The Se-containing component of the atmosphere is removed through a rapid gas exchange process and the CIGS film is annealed to influence the Ga distribution throughout the depth of the film.