New high-speed long-wavelength Al0.48In0.52As/Ga0.47In0.53As multiquantum well avalanche photodiodes

Abstract

We report the operation of a new long‐wavelength (λ=1.3 μm) superlattice avalanche photodiode. The p⁺in⁺ structure, grown by molecular beam epitaxy, consists of a 35 period Al_0.48In_0.52As (139 Å)/Ga_0.47In_0.53As (139 Å) multiquantum well i region sandwiched between p⁺ and n⁺‐Al_0.48In_0.52As transparent layers. dc and high‐frequency multiplications of 32 and 12, respectively, have been measured; the dark current at unity gain is 70 nA. High speed of response with full width at half‐maximum of 220 ps at a gain of 12 and the absence of tails are demonstrated, indicating that carrier trapping in the wells is negligible. In addition, detailed studies of the spectral response for samples with thin layers (103 Å) show extremely clearly the effect of the quantum states of the wells on the photocurrent at room temperature.