Bandwidth enhancement in GeSn-on-Si avalanche photodiodes with a 60 GHz gain-bandwidth-product

We report GeSn-on-Si avalanche photodiodes with a Sn concentration of 2.1 %. The devices exhibit a bandwidth enhancement at high reverse voltages achieving bandwidths up to 3.9 GHz and high gains at 1,550 nm, resulting in a 60 GHz gain-bandwidth-product.