The greater the avalanche gain of carriers in the depletion layer, the longer the avalanche multiplication process takes. Therefore, avalanche multiplication process is limited by "gain-bandwidth product". In the case of high avalanche gain, this limitation may become one of the main factors affecting the response speed of avalanche photodiode. However, at medium gain, compared with other factors that affect the response speed of photodiode, this limitation often does not play a major role, so avalanche photodiode can still obtain high response speed. The gain bandwidth product of modern avalanche photodiode has reached several hundred GHz.

Like the general semiconductor photodiode, the spectral sensitivity range of avalanche photodiode mainly depends on the band gap width of semiconductor materials. Materials used to prepare avalanche photodiodes include III-V compounds, such as silicon, germanium, gallium arsenide and indium phosphide, and their ternary and quaternary solid melts. According to different methods of forming depletion layer, avalanche photodiode has PN junction type (homogeneous or heterogeneous PN junction). Among them, there are general PN junction, PIN junction and N+PπP+ junction), metal semiconductor Schottky barrier type, metal oxide semiconductor structure and other special structures.