Interface between a i/iii/vi2 layer and a back contact layer in a photovoltaic cell

Method according to any one of the above claims, wherein said step is preceded by deposition of said metal without said additional element.

Method according to any one of the above claims, wherein the metal is deposited by sputtering a target (CT) containing said metal, the sputtering being assisted by a plasma containing said additional element during said step.

Method according to any one of the above claims, wherein the metal is molybdenum.

Method according to any one of the above claims, wherein the additional element is at least one element from among:

• nitrogen, to form a nitride as barrier material to the element VI,
• oxygen, to form an oxide as barrier material to the element VI, and
• a metal to form an alloy as barrier material to the element VI.

Method according to any one of the above claims, wherein the element VI is selenium.

Photovoltaic cell comprising:

• an alloy layer of elements I, III and VI, said layer having photovoltaic properties, and
• a contact layer, comprising a metal, under the photovoltaic layer, an intermediate layer between the photovoltaic layer and the contact layer, comprising a compound of metal-element VI,
• wherein said cell additionally comprises, under the layer of the metal-element VI compound, a layer comprising an additional element forming, with said metal, a compound forming a barrier to the element VI.