NOVELTY - A method comprises forming a transparent conductive oxide layer over a substrate; annealing the formed transparent conductive oxide layer; and etching the annealed transparent conductive oxide layer to form roughened surface. Etching comprises exposing the annealed transparent conductive oxide layer to a wet etchant composition selected from e.g. a mixture of hydrochloric acid, hydrogen peroxide, and deionized water having a concentration ratio of hydrochloric acid and hydrogen peroxide relative to the deionized water of 0.25-10%.    USE - The method is for forming transparent conductive oxide useful for solar cell device i.e. crystalline or amorphous silicon-based thin film or tandem or single junction photovoltaic solar cell, or for electrochromic technologies.    ADVANTAGE - During the sputtering process, plasma is ignited in the processing chamber, which naturally heats the substrate, so that no additional heat is provided to the substrate during deposition, such as from the susceptor. When only the plasma is heating for the substrate, the variable of heating through the susceptor is removed and a level of uncertainty is removed. The method achieves a more uniform grain structure in the deposited film as compared to the hot plasma vapor deposition process. It has simpler hardware systems, which are more reliable and more cost effective; more control of transparent conductive oxide film uniformity across large area substrates; and much lower system cost of ownership. The method permits deposition on existing high-volume, in-line glass coating systems. The transparent conductive oxide film may be formed on a substrate that has the desired haze and efficiency to meet the needs of solar cell manufacturing.    DETAILED DESCRIPTION - A method comprises forming a transparent conductive oxide layer over a substrate; annealing the formed transparent conductive oxide layer; and etching the annealed transparent conductive oxide layer to form a roughened surface. Etching comprises exposing the annealed transparent conductive oxide layer to a wet etchant composition selected from a mixture of hydrochloric acid (HCl), hydrogen peroxide (H2O2), and deionized water having a concentration ratio of HCl and H2O2 relative to the deionized water of 0.25-10%; a mixture of HCl and deionized water having a concentration ratio of HCl relative to the deionized water of 0.25-10%; a mixture of nitric acid (HNO3) and deionized water having a concentration ratio of HNO3 relative to the deionized water of 0.25-10%; or a mixture of sulfuric acid (H2SO4) and deionized water having a concentration ratio of H2SO4 relative to the deionized water of 9.25-10%.