Patent ID: 8894867

Claim:
A method for producing a zinc oxide layer on a flexible or rigid substrate by depositing the zinc oxide layer onto said substrate, in which the zinc oxide layer has a crater density and a crater structure that can be adjusted homogeneously and independently of deposition conditions by etching, the method comprising the steps of sputtering zinc oxide on to a substrate to provide a deposited zinc oxide layer, etching the deposited zinc oxide layer in at least first and second etching steps, etching in the first etching step with hydrofluoric acid in a concentration of more than 0.125 wt % to 4 wt %, etching in the second etching step with one of an acid that is not hydrofluoric acid or hydrofluoric acid in a concentration different from the hydrofluoric acid concentration employed in the first etching step, whereby in the first etching step craters are formed in the deposited zinc oxide layer that have a diameter of less than 300 nm, the craters having a density of 5 to 100 μm −2 , and the craters have edges that are smoothed by the etching in the second etching step.