Abstract
The extended wavelength InGaAs material (2.3 μm) was prepared by introducing compositionally undulating step-graded InAsyP1−y buffers with unequal layer thickness grown by solid-source molecular beam epitaxy (MBE). The properties of the extended wavelength InGaAs layer were investigated. The surface showed ordered crosshatch morphology and a low roughness of 1.38 nm. Full relaxation, steep interface and less than one threading dislocation in the InGaAs layer were demonstrated by taking advantage of the strain compensation mechanism. Room temperature photoluminescence (PL) exhibited remarkable intensity attributed to the lower density of deep non-radiative centers. The emission peak energy with varied temperatures was in good agreement with Varshni’s empirical equation, implying high crystal quality without inhomogeneity-induced localized states. Therefore, our work shows that compositionally undulating step-graded InAsP buffers with a thinner bottom modulation layer, grown by molecular beam epitaxy, is an effective approach to prepare InGaAs materials with wavelengths longer than 2.0 μm and to break the lattice limitation on the materials with even larger mismatch.
Highlights
The ternary InxGa1−xAs alloy has gained great success on optoelectronic applications due to the tunable bandgap from 0.9~3 μm, which is corresponding to the atmosphere transmission window [1,2]
Gu et al studied properties of In0.85Ga0.15As on different InxAl1−xAs buffer structures systematically grown by gas-source molecular beam epitaxy (GSMBE) at several advantages, and In0.85Ga0.15As photodetectors with cutoff at 2.5 μm were made based on device-quality epilayer growth [14,19]
Hudait et al reported In0.69Ga0.31As TPV device with step-graded InAsyP1−y buffer, and compared the In0.69Ga0.31As properties with InxAl1−xAs and InAsyP1−y buffers grown by solid-source molecular beam epitaxy (SSMBE), showing that InAsyP1−y displayed ideal characteristics, while InxAl1−xAs presented phase decomposition and rougher surface [20]
Summary
The ternary InxGa1−xAs alloy has gained great success on optoelectronic applications due to the tunable bandgap from 0.9~3 μm, which is corresponding to the atmosphere transmission window [1,2]. The structural property of the SSMBE grown In0.76Ga0.32As epilayer on a compositionally undulating step-graded InAsyP1−y buffer with unequal single layer thickness is investigated in detail by using atomic force microscopy (AFM), reciprocal space mapping (RSM), and cross-sectional transmission electron microscopy (TEM).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
