New type InGaAs/InP heterostructure avalanche photodiode with buffer layer

A new type heterostructure avalanche photodiode (HAPD) is proposed and successfully fabricated by liquid phase epitaxy and Zn-diffusion. The HAPD has been made from a successively grown wafer which consists of In
0.53
Ga
0.47
As light absorption layer, InGaAsP buffer layers and InP avalanche multiplication layer on n-InP substrate. Dark current density of 1 × 10
^-4
Acm
^-2
at 0.9 V
B
is achieved. When illuminating with 1.15 µm light, the diode has a maximum multiplication gain of 880 and an external quantum efficiency of 40%. The quantum efficiency is markedly improved than that of previously reported HAPD.