Memory cells, and methods of forming such memory cells, are provided that include a steering element coupled to a carbon-based reversible resistivity switching material. In particular embodiments, methods in accordance with this invention form a single layer of a carbon-based reversible resistance switching material above a substrate, wherein the single layer of carbon material has a thickness greater than about three monolayers of the carbon-based reversible resistance switching material, and prior to forming an additional layer above the carbon layer, thermally anneal the carbon layer. Other aspects are also provided.