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ABSTRACT: We demonstrate that the electrical quality of junctions fabricated in lattice-mismatched In0.75Ga0.25As on InP grown by molecular beam epitaxy can be improved with the addition of in situ anneals in the buffer layer that separates the substrate from the In0.75Ga0.25As device layers. Near infrared photodetectors fabricated using this material had dark current densities of approximately
2.5 mA/cm2 at a reverse bias of 1 V, which is more than one order of magnitude smaller than commercially available photodetectors grown
using vapor phase epitaxy. Transmission electron microscopy revealed that dislocations due to the lattice mismatch between
the substrate and the epitaxial layer are confined primarily to the buffer layer for all samples studied. No significant differences
in x-ray diffraction spectra or dislocation distribution were observed on samples with and without in situ annealing. Atomic force microscopy indicated that all samples had a crosshatch pattern, and that the average surface roughness
of the sample that contained in situ anneals is a factor of three greater than the sample without in situ anneals.
Journal of Electronic Materials 04/1999; 28(7):887-893. · 1.47 Impact Factor
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ABSTRACT: We demonstrate that high-quality lattice-mismatched In <sub> 0.73 </sub> Ga <sub> 0.27 </sub> As:InP photodetectors for use at 2.2 μm can be grown by molecular beam epitaxy using compositionally graded buffer layers. By investigating various growth conditions, we found that the quality of the active layer material depends on the thickness of the compositionally graded buffer layers and the substrate temperature during the growth of the compositionally graded buffer layers and active layers. The best device performance was obtained from a sample with a 1.0 μm compositionally graded buffer grown at a substrate temperature of 350 °C combined with active layers grown at 400 °C. The typical room temperature dark current at a reverse bias of 1 V for 100×100 μ m <sup>2</sup> photodetectors on this sample was 2 mA/cm <sup>2</sup> . This dark current is a factor of 10 better than that of commercially available devices fabricated from material grown using vapor phase epitaxy. © 1997 American Vacuum Society.
Journal of vacuum science & technology. B, Microelectronics and nanometer structures: processing, measurement, and phenomena: an official journal of the American Vacuum Society 04/1997; · 1.34 Impact Factor
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ABSTRACT: Summary form only given. Operation of photodetectors in the near infrared (1.0-3.0 /spl mu/m) has become increasingly important for a variety of applications. Significant improvements in the performance of these systems can be obtained by integrating these photodetectors in large scale linear and 2-D focal plane arrays (FPAs). InGaAs on InP as photodetector was used. Growth was by molecular beam epitaxy.
Lasers and Electro-Optics, 1996. CLEO '96., Summaries of papers presented at the Conference on; 07/1996
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ABSTRACT: The growth by molecular beam epitaxy of In0.74Ga0.26As is investigated because of its importance as a PV converter for a variety low temperature TPV system configurations. In this work, a linearly graded buffer layer is used to grow high quality In0.74Ga0.26As layers on a lattice mismatched InP substrate. The thickness of the buffer layer and the substrate temperature during the growth of the buffer and active layers were varied in order to optimize the active layer material quality. The resulting p+−i−n+ epitaxial layers were compared using double crystal x‐ray diffraction, spectral response, and current‐voltage measurements. A more conventional PV cell structure was also evaluated using current‐voltage measurements. © 1996 American Institute of Physics.
AIP Conference Proceedings. 02/1996; 358(1):394-405.
