SURFACE MODIFICATION OF POROUS SILICON BY ALUMINUM ISOPROPOXIDE AND ITS IMPACT ON ELECTROLUMINESCENCE

Dilute solutions of aluminum isopropoxide have been used to modify the surface of porous Si in an attempt to find simple chemical approaches to stabilize its electroluminescent response and simultaneously provi de additional details concerning the mechanism of electroluminescence degradation. Both infrared and energy dispersive x-ray spectroscopies confirm that aluminum is incorporated onto the porous Si surface. The modified porous Si has much more stable electroluminescence at lower b ias voltages, and the rate of electroluminescence degradation is very sensitive to the surface temperature. The surface temperature, in turn , is clearly a function of applied bias voltage. Transmission electron microscopy and infrared spectroscopic measurements clearly demonstrat e that the degradation is related to Si nanoparticle oxidation. By inv estigating the degradation rate of porous Si electroluminescence at di fferent temperatures, the activation energy of porous Si oxidation can be estimated.