Electron spin resonance in alkali doped SWCNTs

Abstract

Electron spin resonance (ESR) measurements on SWCNTs doped with alkali atoms (potassium) using a solid state reaction is reported. We find the emergence of the ESR signal of itinerant electrons upon doping with a signal intensity that is comparable to that expected from band structure calculations.The ESR line‐width and microwave conductivity weakly depend on the temperature indicating that doped SWCNTs are bad metals. It is argued to result from the lack of crystalline order in the tubes and the large impurity concentration. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Electronic properties of pristine and modified single-walled carbon nanotubes

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Electron spin resonance study of single‐walled carbon nanotubes

“…Figure 1 shows the ESR response at room temperature; the three samples containing a random distribution of metallic and semiconducting SWCNTs (spectra (a) and (b)) show an asymmetric signal assigned in previous studies 7–11 to conduction electrons from SWCNTs (line 1).…”

Identifying the electron spin resonance of conduction electrons in alkali doped SWCNTs

“…The proportion of the CESR signal intensity to the background signal is I CESR =I bkg % 1 : 500 for saturated doping. We note that this is about a factor 3 higher than that reported on the same samples using solid state vapor doping [13]. The intensity calibration gives that the CESR signal is equivalent to 2 Â 10 À3 S ¼ 1/2 spins per C. To obtain this value, we used that 50 wt% of the sample consists of SWCNTs.…”