Vertically aligned carbon nanotube heterojunctions

The bottom-up fabrication and electrical properties of end-to-end contacted multiwalled carbon nanotube (MWCNT) heterojunctions are reported. The vertically aligned MWCNT heterojunction arrays are formed via successive plasma-enhanced chemical vapor deposition processing to achieve the layered junction architecture. Electron microscopy and current-sensing atomic force microscopy are used to reveal the physical nature of the junctions. Symmetric, nonlinear I–V curves of the as-fabricated junctions indicate that a tunnel barrier is formed between the end-to-end contacted MWCNTs. Repeated high bias I–V scans of many devices connected in parallel fuses the heterojunctions, as manifested by a shift to linear I–V characteristics.