Nonideal Diode Behavior and Bandgap Renormalization in Carbon Nanotube p-n Junctions

作者：Chang Shun Wen^*; Bergemann Kevin; Dhall Rohan; Zimmerman Jeramy; Forrest Stephen; Cronin Stephen B

来源：IEEE Transactions on Nanotechnology, 2014, 13(1): 41-45.

DOI：10.1109/TNANO.2013.2287124

• Bandgap renormalization (BGR)
• carbon nanotube (CNT)
• minority carrier lifetime
• p-n junction
• photodiode
• schottky diode

The p-n junction diodes are formed by electrostatic doping using two gate electrodes positioned beneath individual, suspended single-walled carbon nanotubes (CNTs). These devices exhibit nearly ideal diode behavior within a small bias voltage range near 0 V. At higher bias (>vertical bar 0.2 V vertical bar), nonideal diode behavior is observed arising from Schottky contacts formed between the nanotube and its metal contact electrodes and the presence of electron tunneling between the N- and P-doped regions. We introduce a back-to-back diode model to explain the observed current versus voltage (I-V) characteristics. The reverse saturation current, parallel resistance, and open-circuit voltage dependence on gate voltage provide quantitative evidence for the theoretically predicted doping-induced bandgap shrinkage in CNTs. The minority carrier lifetimes are also estimated from this model.

• 出版日期2014-1