Study of field emission characteristics and surface compositions of carbon and silicon emitters utilizing scanning atom probe

The work function of carbon nanotubes (CNT) is found to be lower than that of other carbon specimens such as graphite and vitreous carbon and is lowered further by hydrogen adsorption. The work function increases by heating the CNT at 500/spl deg/C for 60 min. Depth profiles of surface composition of Si etched by HF and NH/sub 4/F are studied with the scanning atom probe. Hydrogen concentrations in the etched silicon specimens are not uniform and many silicon atoms field evaporated from hydrogen rich areas are detected as Si/sub y/H/sub x/ clusters which are dissociated in a few microseconds.