Predicted carbon-cluster field evaporation from graphite by pulsed-field STM

2020-03-30 08:32:36

carbon field graphite clusters evaporation

责任者: Wu, XH;Wolf, EL 单位: 来源出处: SURFACE SCIENCE, v 366, OCT 20 1996, p 353- 359 摘要: Field evaporation of carbon as positive and negative ions from the clean graphite (001) plane surface under STM pulsed-held conditions has been investigated. We use the charge-exchange model, taking the potential from a simple empirical atomic potential model. The removed carbon atom considered here initially resides in the perfect graphite surface, rather than being an adsorbed atom. Assuming a clean tungsten tip as counterelectrode, threshold electric fields for C-, C+, and C2+ have been obtained. We further consider the possibility of held evaporation of C clusters. Our calculations indicate that C atoms can field-evaporate as members of ionic clusters at much lower threshold fields than a single carbon atom can. We conclude that ionic carbon clusters are favored in held evaporation from graphite, based on lower threshold fields obtained in the charge-exchange model. 关键词: carbon clusters; field evaporation; graphite; scanning tunneling microscopy microscopy; SCANNING-TUNNELING-MICROSCOPE; NANOMETER-SCALE; GOLD; SILICON; SURFACE; ATOM; EMISSION; ENERGY; IONS; TIP ATOM; EMISSION; ENERGY; IONS; TIP