A method includes heating, using a heat source, a reactor vessel including a substrate in a radially central core region of the reactor vessel and introducing, using at least one reactor inlet in an outer wall of the reactor vessel, a precursor gas to the reactor vessel. The at least one reactor inlet is configured to swirling flow of the precursor gas around the radially central core region of the reactor vessel. The material deposits on the substrate from the precursor gas. The method includes removing, using at least one reactor outlet, an exhaust gas from the reactor vessel.