Structural and photoluminescent properties of carbon structures on thick porous silicon

In this work, we studied the properties of thin nanoporous carbon coatings on very thick porous silicon (PS) layers of very high porosity. The PS was obtained by etching pores into crystalline Si wafers in a process controlle d to prevent crack formation during etching and drying. The nanoporous carb on was made by dipping the PS samples in diluted polyvinyl alcohol and subm itting the coating to pyrolysis at different temperatures (in the 513-843 K range). The porous carbon coatings obtained on porous silicon using this m ethod presented good adherence, uniform thickness and good optical transpar ency, the greatest luminescence intensity being obtained at a pyrolysis tem perature of 513 K. Such a composite nanoporous structure of two type IV mat erials may find a large number of future applications, ranging from lumines cent devices to molecular sieves. (C) 2000 Elsevier Science B.V. All rights reserved.