Avalanche multiplication and noise characteristics of low-dark-current GaInAsP/InP avalanche photodetectors

Abstract

High‐performance avalanche photodiodes responding out to 1.25 μm have been fabricated in inverted‐mesa n⁺‐InP/n‐GaInAsP/n‐InP/p⁺‐InP structures. Uniform avalanche gains of 700, dark current densities of 3×10⁻⁶ A/cm² at M=10, and an excess‐noise factor of ∼3, also at M=10, have been measured. The low dark current results from the placement of the p‐n junction in the InP and from the use of a new passivation technique. Pulse‐response rise times, measured with an avalanche gain of 40 and limited by the rise time of the mode‐locked Nd:YAG laser pulse, were less than 160 psec.