110 GHz Si MSM photodetectors

The authors report an Si MSMPD (metal-semiconductor-metal photodetector) with a 3.7-ps response time and 110-GHz bandwidth. They also present an experimental and theoretical study of the factors that are important to the speed of Si MSMPDs, such as the photon absorption length, carrier diffusion length, carrier mean free path, finger spacing, and finger width. They also discuss new possibilities for even faster ( approximately 400 GHz) Si-based high-speed MSMPDs.