Low dark current InGaAs PIN photodiodes grown by molecular beam epitaxy

High-quality InGaAs PIN photodiodes have been made from high-purity layers grown on InP substrate by molecular beam epitaxy. The diodes are top-illuminated mesa-type passivated and planarised by polyimide. The devices exhibit dark current densities as low as 2.3 × 10−5 A/cm2 at −10 V with a breakdown voltage of −80 V. These values are comparable with those obtained by other more conventional growth techniques, and are the best so far reported by MBE.