Low dark current, long wavelength metal-semiconductor-metalphotodetectors

Dark current densities of 0.13 and 0.44 pA/µm2 at biases of 5 and 10 V, respectively, have been obtained for InAlAs/InGaAs metal-semiconductor-metal photodetectors with a 2 µm electrode width and spacing, by placing the electrode tips and contact pads on top of an insulating layer of silicon nitride. This is the lowest known dark current density reported for InAlAs/InGaAs metal-semiconductor-metal photodetectors to date.