Abstract: A method for fabricating high efficiency CIGS solar cells including the deposition of Ga concentrations (Ga/(Ga+In)=0.25?0.66) from sputtering targets containing Ga concentrations between about 25 atomic % and about 66 atomic %. Further, the method includes a high temperature selenization process integrated with a high temperature anneal process that results in high efficiency.

Abstract: A method for high temperature selenization of Cu—In—Ga metal precursor films comprises ramping the precursor film to a temperature between about 300 C and about 400 C in a Se containing atmosphere and at a pressure between about 600 torr and 800 torr. A partial selenization is performed at a temperature between about 300 C and about 400 C in a Se-containing atmosphere. The film is then ramped to a temperature between about 400 C and about 550 C in a Se containing atmosphere and at a pressure between about 600 torr and 800 torr. The film is then annealed at a temperature between about 550 C and about 650 C in an inert gas.

Abstract: A method for forming copper indium gallium (sulfide) selenide (CIGS) solar cells, cadmium telluride (CdTe) solar cells, and copper zinc tin (sulfide) selenide (CZTS) solar cells using laser annealing techniques to anneal the absorber and/or the buffer layers. Laser annealing may result in better crystallinity, lower surface roughness, larger grain size, better compositional homogeneity, a decrease in recombination centers, and increased densification. Additionally, laser annealing may result in the formation of non-equilibrium phases with beneficial results.

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: A method for fabricating high efficiency CIGS solar cells including the deposition of Ga concentrations (Ga/(Ga+In)=0.25?0.66) from sputtering targets containing Ga concentrations between about 25 atomic % and about 66 atomic %. Further, the method includes a high temperature selenization process integrated with a high temperature anneal process that results in high efficiency.

Abstract: A method for fabricating high efficiency CIGS solar cells including the deposition of Ga concentrations (Ga/(Ga+In)=0.25-0.66) from sputtering targets containing Ga concentrations between about 25 atomic % and about 66 atomic %. Further, the method includes a high temperature selenization process integrated with a high temperature anneal process that results in high efficiency.

Abstract: A method for fabricating high efficiency CIGS solar cells including the deposition of Ga concentrations (Ga/(Ga+In)=0.25?0.66) from sputtering targets containing Ga concentrations between about 25 atomic % and about 66 atomic %. Further, the method includes a high temperature selenization process integrated with a high temperature anneal process that results in high efficiency.

Abstract: A method for fabricating high efficiency CIGS solar cells including the deposition of Ga concentrations (Ga/(Ga+In)=0.25?0.66) from sputtering targets containing Ga concentrations between about 25 atomic % and about 66 atomic %. Further, the method includes a high temperature selenization process integrated with a high temperature anneal process that results in high efficiency.

Abstract: A method for detecting leaks during high temperature selenization of Cu—In—Ga metal precursor films comprises positioning a light source on one side of a transparent reaction chamber or aligned with a window in an opaque reaction chamber. The method further comprises positioning a detector opposite the light source and detecting an intensity of light from the light source. Leaks in the seals of the reaction chamber will result in the formation of an opaque film on the walls of the reaction chamber. A decrease in the intensity of light incident on the detector will indicate the presence of the leak. A second method comprises measuring the reflection of the light source off of the reaction chamber wall or a window in the reaction chamber. An change in the reflected light will indicate a leak in the seals of the reaction chamber.

Abstract: A method for high temperature selenization of Cu—In—Ga metal precursor films comprises ramping the precursor film to a temperature between about 350 C and about 450 C in an inert gas and at a pressure between about 1 atmosphere and about 2 atmospheres. A partial selenization is performed at a temperature between about 350 C and about 450 C in a Se-containing atmosphere. The film is then ramped to a temperature between about 450 C and about 550 C in an inert gas and at a pressure between about 1 atmosphere and about 2 atmospheres, followed by an additional selenization step at a temperature between about 450 C and about 550 C in a Se-containing atmosphere. The film is then annealed at a temperature between about 550 C and about 650 C in an inert gas.

Abstract: A method for forming copper indium gallium (sulfide) selenide (CIGS) solar cells, cadmium telluride (CdTe) solar cells, and copper zinc tin (sulfide) selenide (CZTS) solar cells using laser annealing techniques to anneal the absorber and/or the buffer layers. Laser annealing may result in better crystallinity, lower surface roughness, larger grain size, better compositional homogeneity, a decrease in recombination centers, and increased densification. Additionally, laser annealing may result in the formation of non-equilibrium phases with beneficial results.

Abstract: Methods are described for forming CZTS absorber layers in TFPV devices with graded compositions and graded bandgaps. Methods are described for utilizing at least one of Zn, Ge, or Ag to alter the bandgap within the absorber layer. Methods are described for utilizing Te, S, Se, O, Cd, Hg, or Sn to alter the bandgap within the absorber layer. Methods are described for utilizing either a 2-step process or a 4-step process to alter the bandgap within the 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 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 metal chalcogenide layers to impact the band gap and the morphology of the 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: Methods are described for forming CIGS absorber layers in TFPV devices with graded compositions and graded band gaps. Methods are described for depositing a Cu-rich precursor layer followed by a Cu-poor precursor layer. Methods are described for depositing a Cu-poor precursor layer followed by a Cu-rich precursor layer. Methods are described for depositing a Cu-poor precursor layer followed by a Cu-poor precursor layer. Methods are described for depositing a Cu-rich precursor layer followed by removing excess Cu-chalcogenide using a wet etch, followed by a Cu-poor precursor layer. 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.

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: 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 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 for increasing the power output of a TFPV solar panel using thin absorber layers comprise techniques for roughening and/or texturing the back contact layer. The techniques comprise roughening the substrate prior to the back contact deposition, embedding particles in sol-gel films formed on the substrate, and forming multicomponent, polycrystalline films that result in a roughened surface after a wet etch step, etc.

Abstract: Method for forming back contact stacks for CIGS and CZTS TFPV solar cells are described wherein some embodiments include adhesion promoter layers, bulk current transport layers, stress management/diffusion barrier layers, optical reflector layers, and ohmic contact layers. Other back contact stacks include adhesion promoter layers, bulk current transport layers, diffusion barrier layers, and ohmic contact layers.