Field-emission properties of sulfur chain-encapsulated single-walled carbon nanotubes

Abstract

The encapsulation of elemental sulfur inside single-walled carbon nanotube (SWNT) and the consequent formation of sulfur chain-encapsulated SWNT (S@SWNT) is achieved. Raman spectra suggest an enhanced conductivity and electron doping of the SWNT by the sulfur chain encapsulation, which are also consistent withultraviolet photoelectron spectra and thermoelectric measurements. Owing to the enhanced electron concentration and the reduced work function, an enhanced field-emission (FE) current is observed for S@SWNT. Inaddition, a gradual recovery of the suppressed FE current is observed for S@SWNT after the O2 purging in thechamber is terminated, while the permanent failure of FE is observed for the pristine SWNT. Further experimental results collectively demonstrate that the enhanced electron concentration of the relatively n-doped SWNT by sulfur chain encapsulation alleviates the damage inflicted to the emitter tip sites from the oxidative en-vironment generated during FE measurement.