A method of forming an ordered nanorods array in a confined space is used to form a high surface area device where an ensemble of parallel trenches has micrometer dimensions for the width and depth of the trenches, which are decorated with crystalline nanowires radiating from the sidewalls and bases of the trenches. The high surface area device is formed by depositing a conformal crystalline seed coating in the trenches, forming microchannels from these trenches by placing a barrier layer on the open surface of the trenches, contacting the conformal coating with a crystal precursor solution that is caused to flow through the microchannels. In an embodiment, a very high surface area electrode is constructed with ZnO nanowires radiating from the sidewalls and base of trenches formed on a silicon substrate. The device can be a dye-sensitized solar cell.