We report a new method to form reproducible luminescent porous silicon layers in p-type and n-type substrates of low and high resisivity, with minimum apparatus and maximum simplicity. No equipment, formation of electrical contacts, illumination or addition of surfactants is needed. The porous silicon layer is formed by exposing the Si surface to the vapor generated by a dissolution reaction of a metal or Si in a HF/HNO 3 mixture. The PL spectra of the layers have peaks located from 1.85 eV to 2.1 eV. The currentvoltage characteristics of Al/PS/p-Si/Al devices formed on these layers are rectifying and follow an exponential dependence at low forward bias and a power law at high forward bias. ity. We have found that this technique yields uniform and reproducible PS layers with S-band (red, orange) photoluminescence (PL). We will present the method and a basic study of the morphology, electrical and photoluminescence properties of the formed layers.

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We investigated the morphology of layers formed by reaction-induced vapor phase stain etch. The layers consist of irregularly shaped, rough regions with sizes in the order of tens of microns bounded by cracks and separated by smoother regions. The AFM images revealed sub-micron cracks and hillocks with columnar aspect, which might correspond to luminescent Si columns a few nanometers wide.

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