VERY-HIGH-DENSITY, ELECTROCHEMICALLY INDUCED, 2-DIMENSIONAL ELECTRON GASES AT A CHEMICALLY STABILIZED SILICON SURFACE

Silicon/polymer electrolyte interfaces have been realized using polyethyleneoxide + CsCF3S03 as the polymer electrolyte. Such interfaces, when polarized under extreme cathodic conditions, allow one to obtain two-dimensional electron gases of very high density (density ns ~ 1013–1014 cm−2). Considerable improvement in the stability of such systems has been found to occur upon pretreatment of the silicon surface with methanol or hexamethyldisilazane. Silicon/methanol electrolyte interfaces themselves exhibit highly stable characteristics. In either cases the obtained two-dimensional electron gases have been characterized from interfacial capacitance and transconductance measurements. The deduced electron mobility in the very-high-density layers varies as ns-a T−β where T is absolute temperature (a ~ 1/3 to 1/2 and β ~ 1 to 3/2 for 180 K < T < 400 K), suggesting the relevance of a phonon scattering process. © 1990, The Electrochemical Society, Inc. All rights reserved.