A template-based method for preparing ordered porous silicon

A detailed study of a new method for preparing ordered porous silicon (PS) is reported. An Ag@SiO2 two-dimensional template was caused to self-assemble on a silicon surface using the vertical deposition method. Ordered PS was obtained by electrodeless etching of the Si wafer plus template in a mixed solution of HF and H2O2. The ordered PS was characterized using Field Emission Scanning Electron Microscopy, Spectrofluorimetry and Fourier Transform Infrared Absorption Spectroscopy. The diameter of the nanopores is about 500 nm. And the thermal conductivities of the ordered PS were found to be reduced compared to bulk silicon and disordered PS, due to enhanced phonon scattering. Compared with disordered PS, the ordered PS has a lower specific surface area. Straight holes and columnar structure in the ordered PS result in high absorption when the wavelength is longer than 890 nm and a high transmittance in the test range of 400–4000 wavenumbers.