TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Method: The substrate is coiled in the treatment chamber. The atomic layer deposition is carried out in a stoichiometrically controlled ratio using self-limiting reaction(s) involving precursor gases of the groups IB and IIIA elements in a mix ratio that translates into a deposition ratio of the IB and IIIA elements on the substrate and/or by an atomic layer deposition sequence involving greater than or equal to 2 self-limiting single species deposition reactions with precursor gases of the group IB and group IIIA elements; and incorporating a group VIA element into the absorber layer. Incorporating the group VIA element into the absorber layer includes exposing the film to selenium vapor, sulfur vapor, hydrogen selenide (H2Se), hydrogen sulfide (H2S), and/or other selenium- or sulfur-containing compounds. The sequence of atomic layer deposition steps includes the use of metal organic precursors containing Se or S, H2Se, and/or H2S. Incorporating the group VIA element takes place either on a monolayer by monolayer basis or periodically with an exposure period longer than a monolayer deposition cycle or at the end of an absorber layer deposition sequence. The substrate is exposed to precursors or copper (Cu), indium (In), gallium (Ga), aluminum (Al), selenium and/or sulfur and then to reducing agent(s) or proton-donor compound(s). Performing atomic layer deposition of group IB element(s) and group IIIA element(s) includes an atomic layer deposition sequence involving greater than or equal to 2 self-limiting single species deposition reactions with precursor gases of the group IB and group IIIA elements and varying a duration of exposure of the substrate to the precursor gases or varying the sequence of deposition reactions to vary the concentration of the group IB and group IIIA elements in the absorber layer as a function of depth. The sequence of deposition reactions produces a concentration of group IIIA element(s) that is relatively higher at and near a front region and a back region of the absorber layer and relatively lower in a central region of the absorber layer, resulting in a saddle profile for the concentration of the group IIIA element(s) as a function of depth within the absorber layer. The absorber layer is flash heated by raising a temperature of the absorber layer at 5-150degreesC/s. A group VIA element is incorporated before and/or during the flash heating of the absorber layer. Flash heating the absorber layer includes heating to an average plateau temperature of 200-600degreesC for 2-10 minutes. An electrode layer is deposited on the substrate by atomic layer deposition before depositing the group IB and/or IIIA elements. An adhesion layer is formed between the substrate and the electrode layer by depositing a layer of vanadium, chromium, tungsten, or silicon dioxide on the substrate before depositing the electrode layer. A window layer is deposited on the absorber layer by atomic layer deposition, chemical surface deposition or liquid-based atomic layer epitaxy. A transparent electrode layer is deposited on the window layer by atomic layer deposition in the same chamber without removing the substrate between depositions.    TECHNOLOGY FOCUS - ELECTRONICS - Preferred Dimension: The absorber layer has a thickness of 1000-2000 nm.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Materials: The group VIA element is selenium (Se) or sulfur (S). The precursors may include Cu(I) compound(s), Cu(II) compound(s), copper chloride (CuCl), copper iodide, or other copper halides; indium chloride, indium iodide, or other indium halides; gallium triiodide, other gallium halides, Ga(I) salts, gallium chloride, gallium fluoride, or gallium iodide; aluminum chloride, aluminum iodide, other halides, aluminum silicate. The reducing agent or proton donor compound includes water (H2O), hydrogen peroxide (H2O2) or oxygen gas (O2). The group IIIA element includes Ga and/or In. The group IB element includes Cu. The electrode layer includes molybdenum. The molybdenum precursor may be molybdenum chloride, molybdenum iodide, other molybdenum halides, molybdenum pentachloride (MoCl5), or molybdenum disilicide. The tungsten precursor may be tungsten chloride, other halides, or tungsten silicide. The vanadium precursor may be vanadium chloride, vanadium iodide, or other vanadium halides. The chromium precursor may be chromium chloride, chromium iodide, or other chromium halides. The window layer comprises cadmium sulfide (CdS). The cadmium sulfide precursor may be cadmium chloride, cadmium iodide, or other halides. The transparent electrode layer includes zinc oxide (ZnO). The zinc oxide precursor may be zinc chloride, zinc iodide, or other zinc halides.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Materials: The group VIA element is selenium (Se) or sulfur (S). The precursors may include Cu(I) compound(s), Cu(II) compound(s), copper chloride (CuCl), copper iodide, or other copper halides; indium chloride, indium iodide, or other indium halides; gallium triiodide, other gallium halides, Ga(I) salts, gallium chloride, gallium fluoride, or gallium iodide; aluminum chloride, aluminum iodide, other halides, aluminum silicate. The reducing agent or proton donor compound includes water (H2O), hydrogen peroxide (H2O2) or oxygen gas (O2). The group IIIA element includes Ga and/or In. The group IB element includes Cu. The electrode layer includes molybdenum. The molybdenum precursor may be molybdenum chloride, molybdenum iodide, other molybdenum halides, molybdenum pentachloride (MoCl5), or molybdenum disilicide. The tungsten precursor may be tungsten chloride, other halides, or tungsten silicide. The vanadium precursor may be vanadium chloride, vanadium iodide, or other vanadium halides. The chromium precursor may be chromium chloride, chromium iodide, or other chromium halides. The window layer comprises cadmium sulfide (CdS). The cadmium sulfide precursor may be cadmium chloride, cadmium iodide, or other halides. The transparent electrode layer includes zinc oxide (ZnO). The zinc oxide precursor may be zinc chloride, zinc iodide, or other zinc halides.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compounds: The metal organic precursors containing selenium or sulfur include dimethyl selenide, dimethyl diselenide or diethyl diselenide. The precursors may include copper diketonate(s), Cu(II)-2,2,6,6-tetramethyl-3,5-heptadionate (Cu(thd)2)), Cu(II)2,4-pentadionate, Cu(II) hexafluoroacetylacetonate (Cu(hfac)2), Cu(II) acetylacetonate (Cu(acac)2), Cu(II) dimethylaminoethoxide, copper ketoester(s), organocopper precursor(s) containing silicon (Si) or germanium (Ge), and/or other copper precursor(s); dimethylindium chloride, trimethylindium, indium 2,4-pentanedionate (indium acetylacetonate), indium hexafluoropentanedionate, indium methoxyethoxide, indium methyl(trimethylacetyl)acetate, indium trifluoropentanedionate, organoindium precursor(s) containing Si or Ge, and/or other organoindium precursor(s); diethylgallium chloride, Ga(III) 2,4-pentanedionate, Ga(III) ethoxide, Ga(III) 2,2,6,6-tetramethylheptanedionate, tris(dimethylaminogallium), gallium acetate, other Ga(I)-based organometallic precursors, organogallium precursors containing Si or Ge, and/or other organogallium precursors; dimethylaluminum chloride, aluminum butoxide, aluminum di-s-butoxide ethylacetoacetate, aluminum diisopropoxide ethylacetoacetate, aluminum ethoxide, aluminum isopropoxide, aluminum hexafluoropentanedionate, Al(III) 2,4-pentanedionate, Al(III) 2,2,6,6-tetramethyl-3,5-heptanedionate, aluminum trifluoroacetate, trisisobutylaluminum, organoaluminum or organometallic precursors containing Si or Ge, and/or other organoaluminum or organometallic precursors. The reducing agent or proton donor compound includes methanol, ethanol, isopropyl alcohol, butyl alcohol, other alcohols, or formalin. The molybdenum precursor may be molybdenum ethoxide, molybdenum VI oxide bis(2,4-pentanedionate), molybdenum hexacarbonyl, organomolybdenum precursors containing Si or Ge, and/or other organomolybdenum precursors. The tungsten precursor may be tungsten ethoxide, organotungsten precursors containing Si or Ge, and/or other organotungsten precursors. The vanadium precursor may be vanadium tri-n-propoxide oxide, vanadium triisopropoxide oxide, vanadium trisisobutoxide, vanadium III 2,4-pentanedionate, vanadium IV oxide bis(2,4-pentanedionate), vanadium IV oxide bis(hexafluoropentanedionate), vanadium IV oxide bis(benzoylacetonate), organovanadium precursors containing Si or Ge, and/or other organovanadium precursors. The chromium precursor may be chromium III benzoylacetonate, chromium (III) hexafluoropentanedionate, chromium III isopropoxide, chromium III 2,4-pentanedionate, chromium III 2,2,6,6-tetramethylheptanedionate, chromium III trifluoropentanedionate, chromium II acetate, chromium III acetate, chromium III 2-ethylhexanoate, organochromium or organometallic precursors containing Si or Ge, and/or other organochromium or organometallic precursors. The cadmium sulfide precursor may be cadmium 2,4-pentanedionate, cadmium acetate, cadmium formate, dimethylcadmium, organocadmium or organometallic precursors containing Si or Ge, and/or other organocadmium or organometallic precursors. The zinc oxide precursor may be dimethyl zinc, diethyl zinc, zinc N,N-dimethylaminoethoxide, zinc methoxyethoxide, zinc 2,4-pentanedionate, zinc 2,2,6,6-tetramethyl-3,5-heptanedionate, zinc acetate, zinc bis(hexamethyldisilazide), organozinc or organometallic precursors containing Si or Ge, and/or other organozinc or organometallic precursors.    TECHNOLOGY FOCUS - POLYMERS - Preferred Materials: The transparent electrode may include a conductive polymer or poly-3,4-ethylenedioxythiophene (PEDOT).