WAVELENGTH EXTENDED InGaAs/InP PHOTODETECTOR STRUCTURES WITH LATTICE MISMATCH UP TO 2.6%
晶格失配度达2.6%的波长扩展InGaAs/InP光电探测器结构

InP-based metamorphic InGaAs photodetector structures with lattice mismatch up to 2.6% were grown on InAlAs graded buffers with a relatively high mismatch grading rate of 1.1%μm-1 by gas source molecular beam epitaxy. They were compared to the samples with the same structures but smaller lattice mismatch of 1.7% and 2.1% to the InP substrate. Characteristics of the wafers were investigated by the measurements of atomic force microscopy, x-ray diffraction, photoluminescence and device performances. Results show that moderate surface morphology, large degree of relaxation and feasible optical characteristics have been obtained for photodetector structures with lattice mismatchthe of 2.6%. The cut-off wavelength of the device is about 2.9 μm at room temperature, The typical dark current of 2.56 μA at room temperature has been achieved at reverse bias of 10 mV for the photodetector with 300 um diameter.