Scanning Microscopy


We have previously demonstrated that hydrogen atoms on the hydrogen-terminated Si(100)-2xl:H surface can be extracted by applying either positive or negative voltage pulses between an STM tip and the sample surface with a certain tunneling current. This phenomenon suggests that electron excitation and field evaporation both play a role in atom transfer. Under our experimental conditions, hydrogen atoms are extracted in pairs from either a single dimer or from two adjacent dimers in neighboring rows. Hydrogen atoms can also be redeposited onto the Si(100)-2xl:H surface from a tungsten tip, which has picked up hydrogen from the sample surface through the application of prior voltage pulses, to fill out surface silicon dangling bonds preferably with negative sample voltage pulses.

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