  A three-step process has been demonstrated to improve the performance of
photodiode by creating nanocone forest on the surface of photodiode as an
antireflection layer. This high-throughput, low-cost process has been shown to
decrease the reflectivity by 66.1%, enhance the quantum efficiency by 27%, and
increase the responsivity by 25.7%. This low-cost manufacture process can be
applied to increase the responsivity of silicon based photonic devices.
