NANOSCALE ORGANIZED ASSEMBLY OF NANOPARTICULATE TIO2-STEARATE MONOLAYERS THROUGH THE LANGMUIR-BLODGETT METHOD

Nanoparticulate titanium dioxide-stearate (TiO2-St) monolayer was dire ctly obtained using TiO2 hydrosol as the subphase. The atomic force mi croscopy images of monolayer, show that the higher coverage were obtai ned through deposition on the hydrophilic Si(100) surface rather than the hydrophobic Si(100) surface. From the surface photovoltage spectra of TiO2-St monolayer, it can be followed that the photovoltage respon se of the n-type silicones increased by a factor of 25, and 5 times af ter a monolayer of TiO2-St Langmuir-Blodgett (LB) films was transferre d onto hydrophobic and hydrophilic Si surface, respectively. On the co ntrary, the photovoltage response value is reduced by similar to 40 an d 5 times by the deposition of the LB monolayer in the case of the hyd rophobic and hydrophilic p-type Si surface, respectively. It is consid ered that the enhancement of the photovoltage response may be due to t he ordered electrostatic potential orientation of the Si(100)/TiO2-St/ ITO heterostructures. (C) 1997 American Vacuum Society. [S0734-211X(97 )00705-4].