Copper-based chalcogenide photovoltaic device and a method of forming the same

A method for forming a photovoltaic device comprising the

• steps of:
• providing a first conductive material on a substrate;
• depositing a layer of a dielectric material on the first conductive material, the layer of the dielectric material being continuous and being thinner than 10 nm;
• depositing a plurality of precursor materials on the layer of the dielectric material;
• annealing the first conductive material, the layer of the dielectric material and the plurality of precursor materials in a chalcogen atmosphere to form a chalcogenide light-absorbing material on the layer of the dielectric material;
• and
• depositing a second material on the light-absorbing material such that the second material is electrically coupled to the light-absorbing material;
• wherein during the step of annealing:
• the plurality of precursors react to form the chalcogenide light-absorbing material;
• and
• wherein the first conductive material and the dielectric material are selected such that, during the step of annealing, a portion of the first conductive material undergoes a chemical reaction to form:
• a layer of a metal chalcogenide material at the interface between first conductive material and the dielectric material;
• and
• a plurality of openings in the layer of the dielectric material;
• the openings being such to allow electrical coupling between the light-absorbing material and the layer of the metal chalcogenide material;
• and
• wherein the portion of the first conductive material that undergoes the chemical reaction during the annealing expands in volume and applies a tensile stress to a lattice structure of the layer of the dielectric material so that the lattice structure is altered to form a self-organized nano-pattern of openings in the layer of the dielectric material.