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26 October 1999 InAs/Ga1-xInxSb infrared superlattice diodes: correlation between surface morphology and electrical performance
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The structural properties of InAs/Ga1-xInxSb infrared (IR) superlattice layers grown by MBE on GaSb substrates have been investigated using high-resolution X- ray diffraction, atomic force microscopy (AFM), secondary ion mass spectroscopy and photoluminescence (PL) spectroscopy. Excellent layers could be grown with a residual mismatch below 1 X 10-3 showing interference oscillations in the X-ray diffraction pattern and high PL efficiency. IR-photodiodes processed from such layers show high responsivity and low leakage currents. The influence of n- and p-doping on the PL efficiency of IR superlattices has been investigated, showing a stronger decrease of the PL intensity for n-doping than for p-doping. Growing the IR-SLs with an As/In V/III ratio below 5, defects with a size of about 1 to 5 micrometers in diameter are observed in the AFM scans. The surface morphology between the defects remains perfect. The defects do not significantly affect the X-ray diffraction patterns and the PL intensity. In a minority-carrier-device, such as IR- photodiodes, the defects are associated with defect-assisted tunneling currents leading to a strong degradation of the electrical performance. By optimizing the growth conditions the defect density can be significantly reduced resulting in a surface roughness given by the standard deviation of the measured height profile of the AFM measurement below 0.3 nm leading to excellent device performance.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Frank Fuchs, L. Buerkle, Wilfried Pletschen, J. Schmitz, Martin Walther, H. Gullich, N. Herres, and Sabine Mueller "InAs/Ga1-xInxSb infrared superlattice diodes: correlation between surface morphology and electrical performance", Proc. SPIE 3794, Materials and Electronics for High-Speed and Infrared Detectors, (26 October 1999);

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