Unintended Deviation of Fermi Level from Band Edge in Fractal Silicon Nanostructures: Consequence of Dopants' Zonal Depletion

The location of Fermi level in a semiconductor is of utmost importance, thus understanding its relative drift from the expected location contains a lot of technologically significant information. A fabrication process induced spatial deviation in the Fermi level position has been reported here in silicon quantum structures prepared using chemical etching. Experimental (direct) and theoretical Raman spectroscopy analyses (indirect) reveal low dopant concentration in the nanosilicon, which explains several reports on its low conductivity. An experimental dopant mass migration based hypothesis (similar to the zone melting process), duly validated using Raman spectroscopy, has been used to explain the observed phenomenon.