Small-diameter silicon nanowire surfaces
Research output: Journal Publications and Reviews (RGC: 21, 22, 62) › 21_Publication in refereed journal
Related Research Unit(s)
|Journal / Publication||Science|
|Publication status||Published - 21 Mar 2003|
|Link to Scopus||https://www.scopus.com/record/display.uri?eid=2-s2.0-0037459371&origin=recordpage|
Small-diameter (1 to 7 nanometers) silicon nanowires (SiNWs) were prepared, and their surfaces were removed of oxide and terminated with hydrogen by a hydrofluoric acid dip. Scanning tunneling microscopy (STM) of these SiNWs, performed both in air and in ultrahigh vacuum, revealed atomically resolved images that can be interpreted as hydrogen-terminated Si (111)-(1 × 1) and Si (001)-(1 × 1) surfaces corresponding to SiH3, on Si (111) and SiH2, on Si (001), respectively. These hydrogen-terminated SiNW surfaces seem to be more oxidation-resistant than regular silicon wafer surfaces, because atomically resolved STM images of SiNWs were obtained in air after several days' exposure to the ambient environment. Scanning tunneling spectroscopy measurements were performed on the oxide-removed SiNWs and were used to evaluate the electronic energy gaps. The energy gaps were found to increase with decreasing SiNW diameter from 1.1 electron volts for 7 nanometers to 3.5 electron volts for 1.3 nanometers, in agreement with previous theoretical predictions.