In this study, the use of a CO2 supercritical fluid (SCF) and silver (Ag) nanoparticles is shown to improve the electrical contact between a metal and porous silicon (PS). Earlier problems concerning surface roughness are not observed. Scanning electron microscopy (SEM) showed that SCF processing at 100 degrees C with Ag nanoparticles of a diameter of about 100 nm filled the pores of PS. Separate experiments using different concentrations of the silver precursor in the process showed that the size and morphology of the nanoparticles could be controlled. Because of the large reduction in contact resistance that is produced, it is possible to observe a nonlinear current - voltage characteristic at room temperature.
