Short wavelength enhanced phototransistor with n-doped porous silicon layer

A phototransistor with aluminium (Al)/porous silicon (Si)/epitaxial-Si structures was proposed and was fabricated and characterised with short wavelength enhanced operating. We proposed the short wavelength response of the Si-based thin film phototransistor; it can be enhanced by introducing thin porous Si (PS) layer as the base region of transistor. The porous process of device manufacture is suitable for applications in design of visible-light sensitive phototransistors. Experimental results showed that the short wavelength responses in the developed devices were enhanced as compared with the Si-based homojunction transistors, this comparably medium optical gain indicated that the developed Al/PSi/epitaxial-Si heterojunction thin film phototransistor got potential for practical Si-based optical-electron integrated-circuit and biophotonics applications.