InGaAs Photodetectors Cut-off at 1.9μm Grown by Gas-Source Molecular Beam Epitaxy

Using a linear graded In_xGa_1-xAs as the buffer layer, positive-intrinsic-negative wavelength-extended In_0.6Ga_0.4 As photodetectors with 50% cut-off wavelength of 1.9μm at room temperature were grown by using gas-source molecular beam epitaxy, and their performance over a wide temperature range has been extensively investigated. The detectors show typical dark current at bias voltage 50mV and the resistance--area product R₀A of 7nA/765\Ωcm² and 31pA/404kΩcm² at 290K and 210K, respectively. The thermal activation energy of the dark current in the temperature range 250--350K is 0.488eV.