Nanocrystal-size-sensitive third-harmonic generation in nanostructured silicon

Third-harmonic generation (THG) in reflection geometry was studied in nanostructured silicon layers grown by electrochemical porosifying of p-type (110) silicon substrates. An order of magnitude enhancement of the THG efficiency compared to crystalline silicon (c-Si) was observed for the samples prepared on a highly doped substrate, whereas for the samples grown on a low-doped substrate the THG was much less efficient than for c-Si. The finding is discussed in terms of fluctuations of the electric field of the pump-laser irradiation in the layers of anisotropically distributed silicon nanocrystals. Received: 26 July 2002 / Revised version: 9 January 2003 / Published online: 3 April 2003 RID="*" ID="*"Corresponding author. Fax: +7-95/939-1566, E-mail: leo@vega.phys.msu.su