Study and applications of plasma-modified Si and porous Si surfaces

In this work we have studied the electrical, chemical and physical properties of CHx/silicon and CHx/porous silicon (PS). The hydrocarbon (CHx) layer has been deposited by plasma of methane under argon atmosphere. Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) Spectroscopy and photoluminescence have been used to characterize the CHx/p-Si, CHx/PS interfaces and, electrolyte/(CHx/p-Si) and CHx/PS/p-Si structures. The results show that in the case of bare silicon, the CHx layers act as a resistant film to HF electrolyte and can be used as a potential tool for ultra-low thickness for masking and patterning. The deposition of CHx layer on PS shows that CHx/PS/p-Si structure presents a rectifying behaviour and can be used for detecting low concentration of large variety of gases. In addition CHx coated PS samples exhibit more intense luminescence than that observed from an uncoated PS surface where red luminescence is shown .In conclusion, the results clearly demonstrate the interest and applications of Si and PS electrodes coated with hydrocarbon groups.