Munoz, A.G. ; Stempel, Th. ;Skorupska, K. ; Lublow, M. ; Kanis, M. ; Lewerenz, H.J.: Formation of nanoscopic MOS junctions by electrochemical conditioning of n-Si(111) in Ir(III) solutions. Journal of The Electrochemical Society 156 (2009), p. D337-D342
10.1149/1.3153154
Abstract:
Ir nanoislands were electrodeposited from chloride solutions on n-type Si(111) surfaces. The conditioned surface was investigated by electrochemical capacitance measurements, ex situ atomic force microscopy, high resolution transmission electron microscopy, and in-system synchrotron radiation photoelectron spectroscopy (SRPES). The growth of metal particles was accompanied by the formation of an ultrathin oxide layer, conforming to nanodimensioned metal-oxide-semiconductor (MOS) junctions. SRPES Si core-level spectra obtained with surface-sensitive excitation energies show the presence of a SiO2 signal with 30–40% of the oxide signal contribution arising from intermediate oxidation states Si+, Si2+, and Si3+. The valence band spectrum reveals that the Fermi level of silicon is pinned at the gap states of the Si–SiO2 interface at 0.6 eV above the valence band, driving the semiconductor under depletion. The presence of metal particles induces a lateral modulation of the interfacial electric field by the formation of nanoscaled MOS junctions with a Schottky barrier of 0.84 eV, as assumed by extrapolating the behavior of full-covered solid-state MOS junctions.