Porous silicon capping by CVD diamond

In the last few years important research efforts were put concerning the op tical properties of porous silicon (PS). Some interesting devices can be ma de using this new material (ex: L.E.D.s and micro cavities). However, a set of unsolved problems is keeping some distance between PS and its applicati ons. Among these problems are the chemical instability and mechanical weakn ess. In this work, we attempted a CVD diamond protective layer deposition on PS. The optical properties of PS were preserved, as confirmed by photoluminesc ence (PL). The diamond film adhesion was checked by microhardness testing s howing no crack propagation with a load of 200 gf. Nanoindentation measurem ents with 0.1 gf on the resulting surface showed a ten fold increase in har dness with respect to the uncoated material. (C) 1998 Elsevier Science Ltd. All rights reserved.