InSb/CdTe Heterostructures Grown by Molecular Beam Epitaxy

Given the potential for quantum effect device application, the growth, by molecular beam epitaxy, and characterization of InSb-CdTe heterostructures is described. Two procedures for growth of these heterostructures are employed. For the growth of InSb/CdTe double heterostructures, InSb and CdTe layers are grown in separate MBE growth chambers connected via an ultrahigh vacuum transfer module. Here, antimony originating from a compound InSb source oven is used for growth of InSb layers. For the growth of CdTe/InSb multiple quantum well structures, InSb and CdTe layers are grown in a single MBE growth chamber, where antimony is derived from an antimony cracking furnace. To study the optical nature of heteroepitaxially grown InSb, infrared photoluminescence from InSb based double heterostructures has been examined. Despite the transferral of grown layers between III-V and II-VI chambers, luminescence gathered from thick” InSb active layers has shown the existence of recombination features which are similar to bulk InSb. For multilayer structures, grown in a single chamber with the use of an antimony cracker, emphasis has been placed on structural examination by transmission electron microscopy and x-ray diffraction techniques. Examination of multilayer structures by transmission electron microscopy suggests tha t the cracker may be useful for the growth of InSb at low substrate temperatures and low growth rates. Using the cracker, CdTe/InSb superlattice structures have been grown showing multiple satellite peaks in the x-ray diffraction spectrum

Molecular Beam Epitaxy of ZnSe on GaAs Epilayers for Use in MIS Devices

The use of ZnSe on GaAs epilayers (epi) as a pseudo-insulator in field effect device applications is demonstrated. The passivating ZnSe layers are grown on GaAs(epi) by interrupted growth molecular beam epitaxy (MBE) using two separate MBE machines. A thin layer of amorphous arsenic protects the GaAs(epi) during transfer between the MBE systems. When nucleated on the GaAs(epi), the ZnSe grows layer-by-layer as revealed by the reflection high energy electron diffraction pattern generated in the II-VI MBE growth chamber. A study of intensity oscillations in the electron diffraction pattern is further used to understand the initial growth stages of ZnSe on GaAs(epi). The material properties of the ZnSe/GaAs(epi) heterostructure are briefly examined. Even though ZnSe and GaAs have a 0.25% lattice mismatch, transmission electron micrographs show that very thin films (1OOOA) of ZnSe form a coherent and dislocation free interface with the GaAs(epi). In thicker ZnSe films, strain relieving misfit dislocations are observed. Photoluminescence measurements reveal information about the effect of the lattice mismatch on the energy band structure of the ZnSe. For the 1OOOA film, the excitonic features are shifted upwards in energy, and the normally degenerate light and heavy hole valence bands split into two bands. As the 1OOOA of ZnSe is an appropriate thickness for an insulator in a field-effect device, the ZnSe/ GaAs(epi) heterostructure is then used in metal-insulator-semiconductor (MIS) capacitors and transistors. Most prominent, the fabrication of the first depletion-mode field-effect transistors based on the ZnSe/n-GaAs heterointerface are described. The transistors display near ideal characteristics with complete current saturation and cutoff; the channel modulation indicates th a t the Fermi level is not pinned a t the ZnSe/n-GaAs interface. With the success of the depletion-mode transistors, the use of ZnSe and GaAs(epi) in future MIS devices appears promisin

Characteristics of myosin profile in human vastus lateralis muscle in relation to training background.

Twenty-four male volunteers (mean +/- SD: age 25.4+/-5.8 years, height 178.6+/-5.5 cm, body mass 72.1+/-7.7 kg) of different training background were investigated and classified into three groups according to their physical activity and sport discipline: untrained students (group A), national and sub-national level endurance athletes (group B, 7.8+/-2.9 years of specialised training) and sprint-power athletes (group C, 12.8+/-8.7 years of specialised training). Muscle biopsies of vastus lateralis were analysed histochemically for mATPase and SDH activities, immunohistochemically for fast and slow myosin, and electrophoretically followed by Western immunoblotting for myosin heavy chain (MyHC) composition. Significant differences (

Specific features of the luminescence and conductivity of zinc selenide on exposure to X-ray and optical excitation

The set of experimental data on the X-ray-excited luminescence and X-ray induced conductivity of ZnSe are compared to the data on the photoluminescence and photoconductivity. It is experimentally established that the current-voltage characteristics and the kinetics of phosphorescence and current relaxation depend on the type of excitation. It is found that the external electric field influences the intensity and shape of bands in the luminescence spectra. It is shown that the character of excitation defines the kinetics of recombination, charge carrier trapping, and conductivity in wide-gap semiconductors.Comment: 7 pages, 7 figures, published in Fizika i Tekhnika Poluprovodnikov, 2010, Vol. 44, No. 5, pp. 594-59

Chemical Beam Epitaxy of Compound Semiconductors

Contains an introduction, reports on three research projects and a list of publications.3M Company Faculty Development GrantDefense Advanced Research Projects Agency Subcontract 216-25013Defense Advanced Research Projects Agency Subcontract 542383Joint Services Electronics Program Contract DAAL03-92-C-0001National Science Foundation Grant ECS 88-46919National Science Foundation Grant ECS 89-05909National Science Foundation Grant DMR 92-0295

Gas Source Molecular Beam Epitaxy of Compound Semiconductors

Contains an introduction and reports on six research projects.Advanced Research Projects Agency Subcontract 284-25041Joint Services Electronics Program Contract DAAL03-92-C-0001National Center for Integrated Photonic Technology Contract 542-381National Science Foundation Grant DMR 92-02957National Science Foundation Contract DMR 92-02957National Science Foundation Grant DMR 90-2293

Gas Source Molecular Beam Epitaxy of Compound Semiconductors

Contains an introduction and reports on seven research projects.Advanced Research Projects Agency Subcontract 284-25041Joint Services Electronics Program Contract DAAL03-92-C-0001Joint Services Electronics Program Grant DAAH-04-95-1-0038National Center for Integrated Photonic Technology Contract 542-381National Center for Integrated Photonic Technology Grant subcontract 652-693U.S. Army Research Office/ AASERT Contract DAAH04-93-G-0175National Science Foundation Grant DMR 92-02957National Science Foundation Grant DMR 92-02957National Science Foundation Grant DMR 90-22933MIT Lincoln Laboratory Contract BX-5411National Science Foundation DMR 94-0033

Gas Source Molecular Beam Epitaxy of Compound Semiconductors

Contains an introduction and reports on seven research projects.Defense Advanced Research Projects Agency Subcontract 284-25041Joint Services Electronics Program Contract DAAL04-95-1-0038National Center for Integrated Photonic Technology Contract 542-381U.S. Army Research Office/ AASERT Contract DAAH04-93-G-0175National Science Foundation Grant DMR 92-02957Joint Services Electronics Program Grant DAAL04-95-1-0038National Science Foundation Grant DMR 90-22933National Science Foundation Grant DMR 92-02957National Center for Integrated Photonic Technology Contract 542-381MIT Lincoln LaboratoryNational Center for Integrated Photonic Technology Subcontract 542-383National Science Foundation DMR 94-0033