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

Using a linear graded Inx Ga1-xAs as the buffer layer, positive-intrinsic-negative wavelength-extended In0.6 Ga0.4As 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/765Ωcm^2 and 31pA/404kΩcm^2 at 290K and 210K, respectively. The thermal activation energy of the dark current in the temperature range 250-350K is 0.488 eV.