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Control of charge carrier density in mesoporous silicon by adsorption of active molecules
Author(s) -
Kashkarov P. K.,
Osminkina L. A.,
Konstantinova E. A.,
Vorontsov A. S.,
Pavlikov A. V.,
Timoshenko V. Yu.
Publication year - 2007
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200674366
Subject(s) - mesoporous material , silicon , substrate (aquarium) , materials science , dangling bond , adsorption , doping , charge carrier , acceptor , electron acceptor , porous silicon , nanotechnology , chemical engineering , chemical physics , chemistry , photochemistry , organic chemistry , optoelectronics , condensed matter physics , engineering , oceanography , physics , geology , catalysis
We demonstrate that adsorption of donor‐like and acceptor‐like molecules could be used to control the free charge carrier type and density in mesoporous silicon films. Fourier‐transform infrared spectroscopy and electron paramagnetic resonance technique are used to investigate the free charge carriers and surface defects (P b ‐like centers), respectively, in porous films formed from crystalline Si substrate of different conductivity type and doping level. It is shown that the carrier type (electron or hole) and concentration in mesoporous silicon are depended on (i) molecule partial pressure, (ii) doping level of the substrate; (iii) density of defects‐silicon dangling bonds. The free hole concentration in p‐type mesoporous silicon is found to be changed in the range from 10 17 to 3 × 10 19 cm –3 by the adsorption of acceptor‐like molecules. The donor‐like molecule adsorption can switch the type of major carriers from holes to electrons. The obtained results are explained by considering the adsorption‐induced formation of surface states in Si nanocrystals assembling mesoporous silicon. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)