A numerical analysis of a heterostructure InP/InGaAs photodiode

Electrical properties of a heterostructure InP/In0.53Ga0.47- As photodiode have been analyzed numerically. A device simulator, which can handle a heterostructure up to a high voltage operation, was developed for this work. The numerical simulator explains the experimental results obtained regarding photocurrent. The band-gap discontinuities, i.e., 0.22 eV for the conduction band and 0.37 eV for the valence band, were confirmed to be plausible. The photocurrent switching mechanism in the photodiode by bias voltage was clarified through carrier and potential distributions. It was revealed that the photo-excited holes accumulate at the heterointerface, and the switching voltage for photocurrent varies according to the incident optical power level. It is expected that this simulator will be a powerful tool for optimum heterostructure photodiode design.