Dark currents in InAsxSbyP1−(x+y)/InAs photodiodes for 2.5 μm operation

Abstract InAs x Sb y P 1−( x + y ) was grown lattice matched o n InAs by metal-organic vapour phase epitaxy and a p-n junction formed by zinc diffusion. Capacitance-voltage measurements indicate a graded junction. Reverse-biased current-voltage measurements as a function of temperature showed band-to-band tunnelling and diffusion currents, and an additional component which was attributed to thermionic field emission via a deep level defect near the middle of the band gap.