Investigation of InGaAs/InP photodiode surface passivation using epitaxial regrowth of InP via photoluminescence and photocurrent

The viability of epitaxial regrowth of InP to passivate lateral mesa surfaces of lattice-matched InGaAs/InP photodiodes is investigated. The effect of the passivation is quantified via a proposed method that uses multiwavelength photoluminescence to determine the surface recombination velocity (SRV). The effective minority charge lateral diffusion length is also obtained using photocurrent measurements with flood illumination. We propose a methodology where this data can be used together with the SRV to estimate the absorber layer minority charge lifetime. A surface recombination velocity of (3.7±0.1)×104 cms−1 was found for the InGaAs/regrown InP interface, which represents a reduction of 2 orders of magnitude when compared to the value of (6.3±0.1)×106 cms−1 obtained for an unpassivated InGaAs surface.