The off to on switching time and on state consolidation in write-once-read-many-times memory devices based on doped and undoped carbon-sphere/polymer composites

We investigate the write operation in memory devices prepared using thin films of carbon spheres and cross-linked poly(4-vinylphenol) composites. Three types of carbon-spheres (N-doped, B-modified and undoped spheres) are used and their influence on memory characteristics is discussed. These memory devices show write-once-read-many-times (WORM) characteristics with an OFF to ON (high resistance to low resistance) transition at low voltages, of ca. 2 V. We investigate the ON-current, OFF-current and ON to OFF current ratio of devices prepared with composites of the three types of carbon spheres. The results are presented for devices prepared with three different carbon sphere concentration, for each carbon sphere type. The OFF to ON transition occurs in less than 1 μs and the ON-state in the best case is consolidated in less than 10 μs, for a write-operation voltage of 5 V.