TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The thin film absorber layer is formed on a base, where an oxygen content of the absorber layer at a surface region of the absorber layer is reduced compared to another thin film absorber layer comprising silver, copper, indium, gallium, and selenium that is formed in substantially the same manner as the thin film absorber layer comprising silver, copper, indium, gallium, selenium and sulfur. The thin film absorber layer includes a surface region, a bulk region and a transition region disposed between the surface region and the bulk region, where a transition region silver/(silver+copper) molar ratio in the transition region is higher than a surface region silver/(silver+copper) ratio in the surface region. The surface region is characterized by a thickness of less than 300 nm, a gallium/(gallium+indium) molar ratio that is 0-0.3, a sulfur/(selenium+sulfur) molar ratio of 0.1-0.7, and a silver/(silver+copper) molar ratio of 0-0.4. The bulk region is: characterized by an average bulk region gallium/(gallium+indium) molar ratio of less than or equal to 0.5; and at least 400 nm thickness. A surface region sulfur/(sulfur+selenium) molar ratio in the surface region is greater than a surface region silver/(silver+copper) ratio in the surface region. An amount of silver in the absorber layer is large enough to bring gallium towards a surface of the thin film absorber layer. The sulfur changes a bandgap in a surface region of the absorber layer. Preferred Method: Forming the thin film absorber layer includes forming a nascent absorber layer containing silver, copper, indium, and gallium; fully selenizing the nascent absorber layer to form a chalcogenide layer containing silver, copper, indium, gallium and selenium; and incorporating substantial amounts of sulfur into the chalcogenide layer only after full selenization of the nascent absorber layer. Incorporating sulfur forms the thin film absorber layer from the precursor layer. Forming the thin film absorber layer includes forming a precursor layer comprising silver-III flake particles. Selenizing and/or sulfidizing the precursor layer includes selenizing the precursor layer, and incorporating substantial amounts of sulfur only after selenization of the precursor layer has begun, where incorporating sulfur forms the thin film absorber layer. Forming the precursor layer includes forming an indium-silver (AgIn2) alloy phase. Selenizing and/or sulfidizing the precursor includes selenizing the precursor layer; and incorporating substantial amounts of sulfur after full selenization of the precursor layer to form the thin film absorber layer. The method further comprises: altering a minimum band gap of a transition region through use of a chalcogenization rate modifier to adjust a gallium/III concentration of a transition region; altering a shape of a surface region bandgap profile of the absorber layer by changing a molar ratio of sulfur to group VIA elements in the precursor layer; and altering a shape of a bulk region bandgap profile of the absorber layer by changing a ratio of gallium to group III elements in the precursor layer. The precursor layer includes metallic species comprising silver, copper and at least one group IIIA material, where the method further comprises: converting the precursor layer into a thinned layer during a densification period at a first temperature range; reacting the thinned layer at a second temperature range for a transformation period within a second process different from the first process to transform the thinned layer into a planar group IBIIIAVIA compound layer; and replacing a portion of the group VIA material in the planar group IBIIIAVIA compound layer with sulfur by reacting the compound layer in a sulfur environment in a third temperature range, where the absorber layer has a sulfur/(sulfur+selenium) molar ratio of 0.1-0.7 in a surface region of the absorber layer while silver/(silver+copper) molar ratio within the surface region is less than 0.5. Forming the absorber layer includes: annealing with a ramp-rate greater than 1 degrees C/second to 225-650 degrees C; densification and/or alloying between copper, indium, silver, and gallium in an atmosphere containing hydrogen gas; and annealing the precursor layer to form an annealed layer; selenizing and/or sulfidizing the annealed layer with a ramp-rate of 1 degrees C/second in an appropriate vapor to form a thin-film containing at least one chalcogenide compound containing copper, indium, silver, gallium, and (sulfur and/or selenium). Forming the absorber layer includes: selenizing and/or sulfiziding a precursor layer without a separate annealing step in an atmosphere containing hydrogen gas; and densifying and selenizing a precursor layer in one step with a ramp-rate of 1-5 degrees C/second, preferably over 5 degrees C/second, to 225-650 degrees C for greater than 120 seconds in an atmosphere containing either hydrogen selenide or a mixture of hydrogen and selenium vapor (or hydrogen sulfide or hydrogen and sulfur vapor) or selenium vapor, with or without sulfur vapor. An amount of chalcogenization rate modifier in the absorber layer is large enough to bring gallium towards a surface of the thin film absorber layer during the selenizing and/or sulfidizing the precursor layer to form the absorber layer. The chalcogenization rate modifier is silver or gold. Selenizing and/or sulfidizing the precursor layer includes sulfidizing the precursor layer to change a bandgap in a surface region of the absorber layer.