Investigation of Dangling Bond Defects on Silicon Nanocrystals

Figure 3 from the main text.

Spatial mapping of the local density of states of a silicon nanocrystal after the creation of a dangling bond defect. From Fig. 3 of the main text.

The Nazin Lab recently published an investigation of silicon nanocrystal (SiNC) dangling bond (DB) defects, “Visualization and spectroscopy of defects induced by dehydrogenation in individual silicon nanocrystals,” in the Journal of Chemical Physics. In this communication, we use scanning tunneling spectroscopy (STS) to study the impact of dehydrogenation on the electronic structures of hydrogen-passivated silicon nanocrystals supported on the Au(111)surface. Gradual dehydrogenation results, initially, in reduction of the electronic bandgap, and eventually produces midgap electronic states. We also use theoretical calculations to show that the STS spectra of midgap states are consistent with the presence of silicon dangling bonds, which are found in different charge states. Our calculations also suggest that the observed initial reduction of the electronic bandgap is attributable to the SiNC surface reconstruction induced by conversion of surface dihydrides to monohydrides due to hydrogen desorption. Our results thus provide the first visualization of the SiNC electronic structure evolution induced by dehydrogenation and provide direct evidence for the existence of diverse dangling bond states on the SiNC surfaces. The article was published online June 28, 2016, and is available at: http://dx.doi.org/10.1063/1.4954833

Leave a Reply

Your email address will not be published. Required fields are marked *