TECHNOLOGY FOCUS - ELECTRONICS - Preferred Method: The method further involves depositing, during a third period of time, additional Group IIIA element and the Group VIA element; monitoring a second deposition state, during the depositing step, by making a second several measurements of an indicia of the second deposition state; and terminating or attenuating the depositing step at a second critical control point based on a function of the second several measurements of the indicia of the second deposition state. The substrate is cylindrical or planar. The first/second/third period of time is 15-60 minutes. There is a time gap between the depositing steps. A precursor is formed on the substrate or the optional layer on the substrate during at least a portion of the time gap; and is formed by the Group IIIA element and the Group VIA element during at least a portion of the time gap. The function of the first several measurements of the indicia of the first deposition state is a second order derivative, with respect to time, of the first several measurements. The first critical control point occurs when the second order derivative, with respect to time, approaches a threshold value (preferably zero). The function of the second several measurements of the indicia of the second deposition state is a second order derivative, with respect to time, of the second several measurements. The second critical control point occurs when the second order derivative, with respect to time, approaches a threshold value (preferably zero). The indicia of the first deposition state is a temperature of the substrate or the optional layer on the substrate, a refractive index of the substrate or the optional layer on the substrate, or a vapor pressure. The indicia of the second deposition state is a temperature of the substrate or the optional layer on the substrate, a refractive index of the substrate or the optional layer on the substrate, or a vapor pressure. The first deposition state and the indicia of the second deposition state are optionally same. The function of the first several measurements of the indicia of the first deposition state is a first order derivative, with respect to time, of the first several measurements of the indicia of the first deposition state. The first/second critical control point occurs when the first order derivative, with respect to time, falls below a threshold value or rises above a threshold value. The first order derivative, with respect to time, falls below the threshold value when the first order derivative achieves a minimum value. The first order derivative, with respect to time, rises above the threshold value when the first order derivative achieves a maximum value. The function of the second several measurements of the indicia of the second deposition state is a first order derivative, with respect to time, of the second several measurements of the indicia of the second deposition state. The Group IIIA element and Group VIA element form a precursor (IIIA)2(VIA)3 composition on the substrate or the optional layer on the substrate. The optional layer is disposed on the substrate; and is a back-electrode. The optional layer is not disposed on the substrate and the first depositing step deposits Group IIIA element and Group VIA element on the substrate. Preferred Components: The semiconductor layer comprises Cu(In)1-xGaxSe2 or Cu(In)1-x'Gax'(Sey(S)1-y)2.x=0-1;x'=less than or equal to0;andy=less than or equal to1.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The Group IIIA element is Gallium (Ga), Indium (In), Aluminum (Al) or Thallium (Tl). The Group VIA element is Sulfur (S), Selenium (Se), Tellurium (Te), or Polonium (Po). The Group IB element is Copper (Cu), Silver (Ag), or Gold (Au). The IB2VIA composition is Cu2Se. The precursor IIIA2VIA3 composition is (Inx(Ga)1-x')2(Sey(S)1-y)3 or (Inx(Ga)1-x)2Se3. EXAMPLE - No suitable example given.