Tunable hot-carrier photodetector

The wavelength limit (λc) of detection in a conventional photodetector is determined by the activation energy of the semiconductor structure through the relationship: λc = hc/Δ, where Δ also determines the detector noise (dark current) and hence its performance such as the operating temperature. A long wavelength photodetection principle has been demonstrated by using a hot-cold carrier energy transfer mechanism. A detector with Δ = 0.32 eV experimentally shows response up to 55 μm. The extend response is tunable by varying the degree of hot-hole injection.