Negative Differential Conductance of Carbon Nanotube pn Junctions

Negative differential conductance (NDC), discovered by Esaki in degenerately doped p-n junctions, has wide applications for high-frequency amplifiers and oscillators. Zhou et al. [164] observed negative differential conductance in single-walled carbon nanotube p-n junctions.

The method to prepare the p-n junction was introduced in Section 4.4. Device scheme with the SWNT contacted by two Ni/Au electrodes is shown in Figure 18a. A band diagram for the system is shown in Figure 18b by assuming that the tube is highly doped, therefore a p+/n+ junction was formed. Zhou et al. controlled the doping level by changing gate voltage. By setting gate voltage at -9.5 V, NDC was observed at low temperatures as shown in Figure 19. Figure 19A shows negative differential conductance in an

0 0

Post a comment