Distinction investigation of InGaAs photodetectors cutoff at 2.9μm

Using double heterojunction structure with linearly graded InxAl1–xAs as buffer layer and In0.9Al0.1As as cap layer, wavelength extended In0.9Ga0.1As detectors with cutoff wavelength of 2.88μm at room temperature have been grown by using gas source molecular beam epitaxy, their characteristics have been investigated in detail and compared with the detectors cutoff at 2.4μm with similar structure as well as commercial InAs detectors. Typical resistance area product R0A of the detectors reaches 3.2Ωcm2 at 290K. Measured peak detectivity reaches 6.6E9cmHz1/2/W at room temperature.