Characteristics of a Si dual-band detector responding in both near- and very-long-wavelength-infrared regions

A p-type Si homojunction detector responding in both near- and very-long-wavelength-infrared (NIR and VLWIR) ranges is demonstrated. The detector consists of a p++-Si top contact layer, a p+-Si emitter, an undoped Si barrier, and a p++-Si bottom contact layer grown on a Si substrate. Interband and intraband transitions lead to NIR and VLWIR responses, respectively. The responsivity, quantum efficiency, and detectivity at −1V bias and 4.6K are ∼0.024A∕W, 3.7%, and ∼1.7×109cmHz1∕2∕W at 0.8μm, while they are 1.8A∕W, 8.8%, and ∼1.2×1011cmHz1∕2∕W at 25μm, respectively. The background limited infrared performance temperature at ±0.9V bias is 25K.