Abstract
Using a very thin InP/InAsP cap layer and InAsP strained superlattices in a buffer layer, a lattice-mismatched InGaAs/InAsP photodiode with low dark current and very wide wavelength spectral response was fabricated by metalorganic vapor-phase epitaxy. External quantum efficiencies as high as 55% at 0.6 μm, 80%–90% at 0.8–1.9 μm, and 65% at 2.1 μm was obtained. For the 1-mm-diam photodiodes, typical dark current measured at 274 K and at a reverse bias voltage of 0.1 V was as low as 1×10−7 A.