Properties of Mbe Grown Heterostructures of GaAs/InSb and InP/InSb
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PROPERTIES OF MBE GROWN HETEROSTRUCTURES OF GaAs/InSb AND InP/InSb.
M. T. ASOM, E. A. FITZGERALD, F. A. THIEL, R. PEOPLE, D. EAGLESHAM, L. LUTHER, S. K. SPUTZ, AND, L.C. KIMERLING AT&T Bell laboratories, Murray Hill NJ 07974.
Abstract We have employed molecular beam epitaxy in the growth of InSb on GaAs and InP. The transport, optical and structural properties of the films were investigated by in-situ reflection high energy electron diffraction, Hall effect and temperature dependent Hall effect, photoluminescence, transmission electron microscopy and X-ray diffractometry techniques. We report mobilities of up to 32,000 cm2/volt-sec and free electron concentrations of 3x10 16 /cm 3 at room temperature. We have discovered a new defect state in InSb with an energy position of Ec - 0.05 + 0.006eV. Optical and structural measurements reveal that the differences in thermal expansion and lattice mismatch between the substrates and films results in the broadening of the X-ray diffraction peaks and the near gap photoluminescence linewidths. Furthermore, we observe band gap shifts to higher energies of 10meV and 20meV for growth on GaAs and InP, respectively.
Introduction Substantial effort has recently been given to the growth of mismatched semiconductor systems because of the perceived benefits of integration of optical and electronic devices on a single parent substrate. InSb is an attractive material for mid - wavelength (5-7gm) detectors and sources and for galvanomagnetic devices. These applications are possible because of the properties of InSb which include high mobilities, long electron mean free path and small band gap. In order to realize some of these devices, InSb of extremely good electrical quality and low defect density must be grown. Several authors have recently reported on the growth of InSb on Si and GaAs[1,2,3,4]. We report on the growth of InSb on GaAs, InSb and InP substrates. Our results reveal that in spite of the large thermal expansion and lattice parameter mismatch we have successfully grown InSb of specular morphology and high electron mobility. We find that the thermal and lattice mismatch cause broadening in both the X-ray and photoluminescence spectra and in addition causes shifts to higher energies of the band-edge luminescence.
Experimental The MBE system used in this study was a Riber EVA-32 chamber with effusion sources and electron beam sources. The background pressure during growth was
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