Study by scanning tunneling microscopy of hydrogen adsorption and desorption on Si111 7 x 7 at room temperature and at high temperature.
An overview is given on the use of scanning tunneling microscopy (STM) for investigation of the adsorption of hydrogen on Si(111)7 x 7 both at room temperature and at elevated temperature to finally obtain a hydrogen-saturated surface of Si(111). The initial stages are characterized by high reactivity of Si adatoms of the 7 x 7 structure. After adsorption of hydrogen on the more reactive sites in the beginning of the adsorption experiments a regular pattern, which is different for room and elevated temperature, is observed for the less reactive sites. In agreement with previous work, local 1 x 1 periodicity of the rest atom layer and the presence of di- and trihydride clusters is observed for hydrogen-saturated surface. STM has also been used to characterize surfaces from which the hydrogen atoms have been removed by thermal desorption. Finally, tip-induced desorption by large positive sample-bias voltages and by increasing the tunneling current will be described.
Kraus
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A
Martin-Luther-Universität Halle-Wittenberg, Fachbereich Physik, 06099 Halle, Germany.
Hanbücken
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M
Koshikawa
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T
Neddermeyer
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H