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  • 1
    Electronic Resource
    Electronic Resource
    Low-level photomodulation of exciton absorption in CdTe single quantum wells (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 1196-1202 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An optical nonlinearity at very low light levels in a CdTe/CdZnTe single quantum well at 4 K is reported. Excitation above the band gap produces a significant decrease in the heavy-hole exciton absorption at intensities down to μW/cm2. The dependence of the change in absorption on the pump intensity is sample dependent and is strongly sublinear. At low pump intensity the recovery of the absorption after switching off the pump is exponential with a time constant of about 150 ms, which is nearly independent of pump intensity up to ∼3 mW/cm2. Above 30 μW/cm2 an additional process on a time scale ∼100 μs is observed. The rise time after turning on the pump varies inversely as pump intensity. It is shown that the nonlinearity arises from the presence of excess electrons in the CdTe quantum well, which reduce the excitonic absorption by phase-space filling. These electrons are charge compensated by holes trapped in the barrier. The time and intensity dependence of the optical nonlinearity can be fitted by a kinetic model of the trapping, in which a range of traps with different recovery times participates. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360357
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  • 2
    Electronic Resource
    Electronic Resource
    Critical thickness in epitaxial CdTe/ZnTe (1990)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 56 (1990), S. 292-294 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The critical thickness for coherent growth of CdTe on ZnTe by molecular beam epitaxy is assessed by reflection high-energy electron diffraction, low-temperature photoluminescence, and transmission electron microscopy. The value is found to be 5 monolayers for this high mismatch system (6%). As opposed to similar studies on III-V and Si-Ge systems, there is no evidence of island formation before relaxation by dislocations at the interface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.102812
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  • 3
    Electronic Resource
    Electronic Resource
    Low-temperature refractive indices of Cd1−xMnxTe and Cd1−yMgyTe (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 82 (1997), S. 5086-5089 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The refractive indices of Cd1−xMnxTe and Cd1−yMgyTe (0〈x〈0.28 and 0〈y〈0.70) were determined by analyzing interference fringes in reflectivity spectra of thin films grown by molecular beam epitaxy. It is shown that their dispersions in the transparent region at 4 K are well described by a Sellmeier relation. These results have been applied to grow CdMnTe/CdMgTe Bragg mirrors incorporated in a II–VI microcavity operating in the strong exciton-photon coupling regime. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.366383
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  • 4
    Electronic Resource
    Electronic Resource
    Optical study of residual strains in CdTe and ZnTe layers grown by molecular beam epitaxy on GaAs (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 235-237 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Residual strains in (001) and (111) thick layers of CdTe and ZnTe grown by molecular beam epitaxy on nominal or slightly tilted (001) GaAs have been investigated by reflectance, photoluminescence, and optical pumping experiments at low temperature. Strains are found to be independent of both layer orientations and thicknesses in the range 2–6 μm. They are compressive ≈−0.5×10−3 in CdTe and tensile ≈10−3 in ZnTe. Estimates of thermal expansion effects show that they are the dominant cause of residual strains in these heterostructures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.101917
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  • 5
    Electronic Resource
    Electronic Resource
    Growth of (111) CdTe on tilted (001) GaAs (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 828-830 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Twin-free growth of (111) CdTe on (001) GaAs is reported for substrates tilted around the [11¯0] axis, i.e., exposing Ga dangling bonds at the terrace edges. Layers grown on nominally (001) substrates and tilted substrates are characterized by double crystal x-ray diffraction, low-temperature reflectivity and photoluminescence, channeling, and high-resolution transmission electron microscopy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.100859
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  • 6
    Electronic Resource
    Electronic Resource
    Optical properties of CdTe/CdZnTe wires and dots fabricated by a final anodic oxidation etching (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 1635-1637 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A two step etching process has been used to fabricate wire and dot nanostructures from CdTe/CdZnTe quantum wells with high optical qualities. Wires and dots are first etched by the usual process of electron beam lithography and ion beam etching then, anodic oxidation is used to etch nanostructures to their final lateral sizes. We have observed remarkable improvements in the optical properties of these nanostructures as compared to the single step etching process. Their photoluminescence spectra are similar to that of the reference quantum well, with an exciton linewidth of about 3 meV, even for the smallest wires (100 nm) and dots (250 nm) which were studied. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.113876
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  • 7
    Electronic Resource
    Electronic Resource
    Annealing effect on the shape of CdTe/ZnTe quantum wells (1992)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 60 (1992), S. 2797-2799 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on the effect of thermal annealing on thin (001) CdTe/ZnTe single quantum wells. We found that the interdiffusion strongly modifies the optical spectra: (i) besides the expected blue shift, a strong reduction of the linewidth is observed in a first stage of annealing; we attribute this effect to a complete elimination of the larger islands present at the interface, (ii) in a second stage, "usual'' interdiffusion occurs, with a slow rate in agreement with the diffusion coefficient extrapolated from reported self-diffusion data at higher temperatures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.106831
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  • 8
    Electronic Resource
    Electronic Resource
    Microgun-pumped semiconductor laser (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 62 (1993), S. 796-798 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We demonstrate the feasibility of a novel microgun-pumped semiconductor laser. This is the most compact (a few cm3) and the lowest threshold electron-beam-pumped semiconductor laser ever reported. The electron source is provided by a 104–105/mm2 array of field emissive microtip cathodes each of 1.5 μm diam. The laser operates below 10 kV and below 1 A/cm2. Laser action in a quasi-cw mode with 5 μs pulses at 2 kHz has been obtained between 90 and 300 K with CdTe-CdMnTe graded index separate confinement quantum-well heterostructures, as well as with GaAs-GaAlAs structures. Since neither doping nor ohmic contacts are needed, the microgun laser can use all direct gap semiconductors. It appears as a viable solution for making compact II-VI lasers in the visible domain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.108581
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  • 9
    Electronic Resource
    Electronic Resource
    Spectroscopic study of CdTe layers grown by molecular-beam epitaxy on (001) and (111) Cd0.96Zn0.04Te substrates (1989)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 1338-1346 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The optical properties of CdTe grown by molecular-beam epitaxy are investigated by means of high-resolution photoluminescence, reflectivity, transmission, and resonant excitation spectroscopy. The CdTe epilayers are grown on (001)- and (111) B-oriented Cd0.96Zn0.04Te substrates. Sharp and strong lines associated with impurity bound exciton recombination dominate the spectra and indicate a good crystalline quality as well as a low level of impurity contamination. For the donor bound exciton lines, two electron transitions are observed which allow an identification of the chemical nature of the donors (probably Ga) by comparison with the data previously obtained on bulk material. For the acceptor lines, however, the shallow states which contribute to the spectra are different from those reported in the bulk and seem correlated with more complex centers. This study also reveals the importance of the residual strain contribution. Moreover, the marked difference observed for the optical properties between the (001) and the (111) epilayers spectra clearly evidence the change in the incorporation rate of impurities and/or grown-in defects density with the growth direction. The best spectra are obtained for the (001)-oriented CdTe layers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.344433
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  • 10
    Electronic Resource
    Electronic Resource
    Implantation-enhanced interdiffusion of CdTe-ZnTe heterostructures (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 2524-2534 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Implantation-enhanced interdiffusion of CdTe-ZnTe strained heterostructures is studied by photoluminescence, channeling, transmission electron microscopy, and secondary-ion-mass spectrometry. In the tellurides, implantation defects significantly diffuse and anneal out during implantation, so that only residual extended defects are found, at depths several times greater than the implantation projected range Rp. As a result, interdiffusion is achieved during the implantation, and not during the subsequent annealing which only serves to eliminate the residual defects, thereby restoring the optical properties of the heterostructures. Evidence has been found for trapping of residual defects at the interfaces, perhaps due to strain, and of slower diffusion in multiple quantum wells than in bulk material. These interface-trapped defects are quite hard to anneal out, so that single quantum wells exhibit poor optical properties after implantation and annealing, while multiple quantum wells give rise to nice photoluminescence spectra with sharp blue-shifted lines and appear as promising candidates to realize lateral confinement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354693
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