TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: In the method (M1), the source material comprises any one of solid source of Te, vapor source of Te, solid source of Cd, vapor source of Cd, and solid CdTe source material that yields the amount of Te and the amount of Cd. The Cd is delivered from the source material to the substrate at an atomic percentage of Cd up to 10 times the atomic percentage of the Te. The Te is delivered from the source material to the substrate at an atomic percentage of Te up to 10 times the atomic percentage of the Cd. The material has a minority carrier lifetime of at least 10 ns. The additional amount of Te or Cd is provided during a thermal treatment of the material after deposition process; and is sufficient to form an additional layer of a second material consisting essentially of Te or Cd. The deposition process is selected from physical vapor deposition, close-space sublimation, vapor transport deposition, sputter deposition, electrodeposition, electroless deposition, metal organic chemical vapor deposition, spray deposition, screen print deposition, and/or application of nanostructures (preferably physical vapor deposition, close-space sublimation, and/or vapor transport deposition); and is conducted at essentially vacuum pressure and at 250-700 degrees C. The substrate comprises a CdS material. The method (M1) involves providing to a deposition process a source material comprising an amount of Cd and an amount of Te in the non-stoichiometric ratio and an amount of the additional element (e1). The acceptor dopant is selected from Column 1B, Column 1A, Column 5B, or Column 5A; the donor dopant is selected from Column 3B, Column 3A, or Column 7B; and the isoelectronic dopant is selected from Column 2B plus minus Column 2A, Column 6B or Column 6A. The non-stoichiometric ratio is a Te-rich ratio and the additional element is selected from Column 1B or Column A (preferably Cu, Ag, Au, H, Li, Na, or K); and is a Cd-rich ratio and the additional element is selected from Column 5B or 5A (preferably V, Nb, Ta, N, P, As, Sb, and Bi). The net acceptor density of the layer of the material is at least 1015/cm3. In the method (M2), the polycrystalline CdTe layer further comprises either a net acceptor density of at least 108/cm3 or a net donor density of at least 108/cm3. The method (M2) further involves subjecting the exposed surface to a preconditioning process prior to the deposition of the metal layer to produce a preconditioned exposed surface comprising either a Te-rich stoichiometry or a Cd-rich stoichiometry, where the preconditioning process is selected from at least one of: etching the exposed surface using an etching process selected from chemical etching process, physical etching process, and/or thermal etching process; contacting the exposed surface to a vapor comprising Cd, and/or Te; and depositing Cd or Te onto the exposed surface to form a layer of pure Cd or pure Te on top of the exposed surface. The method (M2) further involves depositing an interface layer comprising highly doped ZnTe onto the exposed surface prior to depositing the metal layer on the interface layer, where the highly doped ZnTe comprises at least one element selected from Column 1A, Column 1B, Column 5A, Column 5B, Column 3A, Column 3B, and Column 7B. The contact layer comprises a metal layer; and further comprises a first interface layer comprising intrinsic ZnTe deposited onto the exposed surface and a second interface layer comprising a metal alloy deposited onto the first interface layer prior to depositing the metal layer onto the second interface layer, where the metal alloy comprises a first element selected from Column 1A or Column 1B and a second element selected from Column 5A or Column 5B (preferably the metal alloy consists of TiP). The acceptor dopant is selected from Column 1B, Column 1 A, Column 5B, or Column 5A; the donor dopant is selected from Column 3B, Column 3A, or Column 7B; and the isoelectronic dopant is selected from Column 2B or Column 2A. The pre-conditioned exposed surface consists of Te-rich stoichiometry, and the additional element is selected from Column 1B or Column 1A (preferably Cu, Ag, Au, H, Li, Na, or K); and consists of Cd-rich stoichiometry, and the additional element is selected from Column 5B or Column 5A (preferably V, Nb, Ta, N, P, As, Sb, and Bi). The polycrystalline CdTe layer consists of p-CdTe, n-or CdTe. The metal layer consists of a metal selected from Mo, Ti, Ni, Al, Nb, W, Cr, and Cu. EXAMPLE - No suitable example given.