The Surface Photovoltaic and Photoluminescent Evolution of a Silicon Nanoporous Pillar Array for Different Etching Times

A series of silicon nanoporous pillar array (Si-NPA) samples are prepared with different times of hydrothermal etching, and their surface morphologies are characterized. A systematic study on the evolution trend of the surface photovoltage and photoluminescence spectra discloses that the adoption of a prolonged etching time will increase the native degree of oxidation and decrease the interfacial states density localized in the SiO_x matrix. These results might be helpful for designing Si-NPA-based semiconductor nanosystems with optimized physical properties.