Si-based optical devices using porous materials

This paper deals with Si-based optical devices using porous materials. We have developed four types of light emitting devices to improve electroluminescence (EL) properties from porous Si (PS) use. The pn heterojunction between microcrystalline silicon carbide (μc-SiC) and PS showed remarkable improvements in EL brightness and stability. The junction between indium tin oxide (ITO) and PS anodized under the UV illumination (UV-PS) and the ITO/porous SiC junction exhibited green EL and blue EL, respectively. The junction between ITO and PS anodized with a high current density above 700 mA/cm2 (HC-PS) achieved a low threshold voltage of light emission (Vth) of less than 5 V. These results indicate that a multi-color light emitting device with a Vth of less than 5 V can be developed using porous materials. Furthermore, using PS, we demonstrate all optical logic gates such as an optical inverter and an optical NOR gate. The light emitting devices and the optical logic gates using porous materials point to the possibility of a Si-based optical computing device.