Photophysical properties of nano Si/SiOx composites in Al/composite/mono Si structures for green light emitting and photodetector-Schottky diodes

The concept of the self-formation of a nanocrystallite (nc-) Si/SiOx:SizOyA l nanocomposite at the Al/oxidized porous silicon interface in the result o f solid-phase processes between Al and oxidized porous Si (PS) and the infl uence of its composition on photophysical properties were developed and exp erimentally confirmed for the Si chip with optical intra-chip interconnect consisting of light emitting and photodetector diodes and alumina waveguide on oxidized PS surface with aluminum electrodes. The peculiarities of nano composite photophysical properties (the refractive index, photoluminiscence (PL) peak situation, PL spectrum shape in the green range) have been shown to be due to the quantum confinement effects (revealed by XPS, Raman spect roscopy) and depend on the Al presence in the nanocomposite (obtained by XP S, IR spectroscopy). The experimental confirmation of this concept is (i) t he shift of the nc-Si valence band relatively to that of monocrystalline Si (c-Si) on 0.2-0.7 eV for nc-Si size in 2.5-6.5 nm range; (ii) the decrease of Si nanocrystallite size in the Al presence; (iii) the approach of the v alue of the refractive index of nc-Si:SiO:Si2O3: SizOyAl nanocomposite at l ambda = 236 nm to that of porous Si with 45% porosity and (iv) the stable g reen PL spectra in the SizOyAl presence in the nanocomposite, (C) 2001 Else vier Science Ltd. All rights reserved.