Array of single-walled carbon nanotube intrajunction devices fabricated via type conversion by partial coating with β-nicotinamide adenine dinucleotide

The fabrication of aligned single-walled, carbon nanotube (SWCNT) intratube junction devices by partially coating pristine SWCNTs with a β-nicotinamide adenine dinucleotide (NADH) solution and subsequent annealing at 150 °C is reported. Gate-bias-dependent rectification behavior is observed with a rectification ratio of >10³ at ±1 V. A comparative study with p-n-junction devices of randomly networked SWCNTs confirms the advantage of using aligned SWCNTs with substantially better rectifying characteristics due to the selective removal of metallic tubes by electrical breakdown. The gate dependence of the intratube p-n-junction in the forward and backward directions is attributed to the difference in the shift of the Fermi levels (forward bias) and the enhanced direct tunneling (reverse bias), as suggested by band-diagram modeling. This work suggests a potential application of aligned SWCNT intratube p-n-junction devices in the future of nanoelectronic circuits. Intratube p-n junctions made of well-aligned pristine and nicotinamide adenine dinucleotide (NADH)-coated single-walled carbon nanotubes (SWCNTs) exhibit gate-dependent rectifying characteristics with low contact resistance and an ideality factor of approximately two. This work shows the easy fabrication of SWCNT intratube p-n-junction devices via growth of well-aligned SWCNTs and type-conversion with NADH coating, which will be widely used as a building block of future nanoelectronic circuits.