PHOTODIODE AND PHOTODETECTOR COMPRISING AN INTEGRATED SERIES OF PHOTODIODES

摘要

A photodiode consists of an undoped light-absorbing region contiguous with one doped region of a pair of doped regions forming a quantum mechanical tunnelling pn junction having a thickness of the order of the mean free path of an electron. A number of the photodiodes are integrated in series with the light absorbing regions being progressively thicker with distance from an incident light receiving surface. For maximum effectiveness with monochromatic light, the thickness and doping of the regions are tailored to produce similar quantities of carriers from the light. A nine section GaAs structure with 50 ANGSTROM thick n+ and p+ tunnelling junction regions has a 90% quantum efficiency and delivers a 5 volt output with a 0.35 picosecond transit time.