A memory cell may include an active electrode, an inert electrode, and a dielectric positioned between them. A forward electrical bias between the electrodes may result in the formation of a conductive bridge between them. A reverse electrical bias may result in the dissolution of the conductive bridge. The memory cell may include nanotube structures formed within the dielectric, where the nanotube structures define columns between the active electrode and the inert electrode. A memory device may include multiple such conductive bridge memory cells. A method of forming a memory cell may include positioning an active electrode onto a substrate, positioning a dielectric layer onto the active electrode, forming nanotube structures within the dielectric layer while positioning the dielectric layer, where the nanotube structures define columns within the dielectric layer, and positioning an inert electrode onto the dielectric layer.