OPTICAL AND ELECTRICAL-PROPERTIES OF POROUS SILICON

The photoluminescence, photoconductivity, optical absorption, and temp erature dependence of the resistance of porous silicon have been studi ed. The silicon was separated from its substrate of the original singl e-crystal silicon. The photoluminescence spectra at 77 K reveal a subs tantial difference between the surfaces of the porous silicon close to and far from the substrate. The optical absorption edge corresponds w ell to the long-wave par-t of the spectra of the photoluminescence and the photoconductivity. The temperature dependence of the resistance o f the porous silicon is described by an activation law with an activat ion energy of 0.33 +/- 0.05 eV.