PHYSICAL-MECHANISM OF HYDROGEN DEPOSITION FROM A SCANNING-TUNNELING-MICROSCOPY TIP

We report on the first successful deposition of individual hydrogen at oms from a tungsten tip of a scanning tunneling microscope onto a mono hydride Si(100)-2x1:H surface. Hydrogen atoms adsorbed on the tungsten tip are first diffused to the tip apex from the surroundings of the t ip by the application of +3.5 V bias to the sample for approximate to 300 ms, and subsequently deposited onto the surface by the application of -8.5 V 300 ms pulses to the sample. The physical mechanisms involv ed are hydrogen diffusion on the tip via field-gradient-induced diffus ion and hydrogen deposition due to electronic excitation.