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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 78 (1956), S. 1955-1958 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 87-94 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The nature of keV ion damage buildup and amorphization in AlxGa1−xAs at liquid-nitrogen temperature is investigated for various Al compositions using Rutherford backscattering channeling, transmission electron microscopy, and in situ time-resolved-reflectivity techniques. Two distinct damage buildup processes are observed in AlxGa1−xAs depending on Al content. At low Al content, the behavior is similar to GaAs whereby collisional disorder is "frozen in'' and amorphization proceeds with increasing dose via the overlap of damage cascades and small amorphous zones created by individual ion tracks. However, some dynamic annealing occurs during implantation in AlGaAs and this effect is accentuated with increasing Al content. For high Al content, crystallinity is retained at moderate ion damage with disorder building up in the form of stacking faults, planar, and other extended defects. In the latter case, amorphization is nucleation limited and proceeds abruptly when the level of crystalline disorder exceeds a critical level. The amorphization threshold dose increases with increasing Al composition by over two orders of magnitude from GaAs to AlAs. Dynamic annealing and damage creation processes during implantation compete very strongly in AlxGa1−xAs even at liquid-nitrogen temperatures. This behavior is discussed in terms of both the availability of very fast mobile defects and bonding configurational changes related to the Al sublattice in AlxGa1−xAs of high Al content. © 1995 American Institute of Physics.
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  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 1481-1487 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Deep levels and carrier compensation created in undoped metal-organic chemical-vapor deposition grown GaAs by low fluence proton irradiation (1×108−1×1010 cm−2) are investigated by the deep level transient spectroscopy technique and capacitance-voltage profiling. At least five main electron traps are observed after room-temperature irradiation in addition to the EL2 present in the as-grown material. Irradiation generates additional EL2, which annihilate at much lower temperatures than one would expect for isolated EL2. However, with further increase in irradiation fluence, the magnitude for this additional increment begin to decrease. The apparent decrease in the EL2 peak is accompanied by an increase of a broad peak in the deep level transient spectroscopic spectrum. This broad peak has a highly nonexponential capacitance transient and it is suggested to result from the interaction of the additional EL2 with EL6. One of the observed traps, with energy level, (Ec−0.40) eV, has not previously been reported in proton irradiated GaAs. The signature of this trap resembles that of EL5 and is quite stable at moderate annealing temperatures; annihilating completely only at a temperature of ∼600 °C. This level shows a saturation effect with increasing irradiation dose and we believe it is related to complex defect-impurity formation. The temperature dependence of the carrier profiles reveals some complex behavior of carrier compensation, including acceptor- and donor-like properties of the various traps. © 1995 American Institute of Physics.
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 5255-5261 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have recently shown [P. N. K. Deenapanray et al., Appl. Phys. Lett. 77, 626 (2000)] that four electron traps S1(Ec−0.23 eV), S2(Ec−0.46 eV), S3(Ec−0.72 eV), and S4(Ec−0.74 eV) are introduced in rapid thermally-annealed (RTA) SiO2-capped n-type GaAs epitaxial layers. In the present study, we have used deep level transient spectroscopy to investigate the electronic and annealing properties of these deep levels. The electron emission kinetics of S1 is enhanced by an electric field, and the activation energy of S1 decreases linearly from ∼233 to ∼199 meV when the field is increased from 7.5×104 to 13.4×104 V cm−1. The intensities of S1, S2, and S4 show Arrhenius-like dependencies on the RTA temperature, which relate to the outdiffusion of Ga atoms into the SiO2 layer. The intensity of S2(VGa–SiGa) also increases exponentially with the square of the annealing time for RTA at 800 °C. Isochronal annealing experiments show that S1 and S2 are thermally stable below 500 and 400 °C, respectively. S4, which is a member of the EL2 family, is stable up to 600 °C. Secondary defects are introduced during isochronal annealing above 400 °C, and some of these defects are thermally stable at 600 °C. © 2000 American Institute of Physics.
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 7964-7966 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effect of ion implantation-induced interdiffusion on the resonant wavelength of GaAs/AlxOy distributed Bragg reflectors is investigated. As interdiffusion becomes stronger, the resonant wavelength is seen to redshift. Shifts of more than 60 nm could be achieved for center wavelengths around 800 nm. A model is proposed to explain this behavior. This model agrees well with previous lateral oxidation studies. © 1999 American Institute of Physics.
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 5343-5347 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The evolution of the sheet resistance (Rs) of n-type and p-type conductive InP layers during proton irradiation and the stability of the formed isolation during postirradiation annealing were investigated. It was found that the threshold dose (Dth) to convert the conductive layer to a highly resistive one is different for n- and p-type samples with similar initial free carrier concentrations. From our results, one infers that the antisite defects and/or related defect complexes formed by the replacement collisions are the carrier trapping centers, where InP is responsible for electron trapping and PIn for the hole trapping. A time dependence of the Rs was observed after each irradiation step to doses of ≅Dth and higher. This time variation is related to metastable processes involving free carriers. The thermal stability of the isolation of n-type samples is limited to temperatures lower than 200 °C, irrespectively of the irradiated dose. For p-type samples the thermal stability of electrical isolation is extended to 450–500 °C. © 2001 American Institute of Physics.
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 6786-6789 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Proton irradiation with subsequent rapid thermal annealing was used to investigate intermixing of InGaAs/GaAs and InGaAs/AlGaAs quantum wells. Large photoluminescence (PL) energy shifts were observed in both materials. Comparatively, InGaAs/AlGaAs samples showed larger PL energy shifts than InGaAs/GaAs samples because of the presence of Al in the barriers and also better recovery of PL intensities, which is mainly due to dynamic annealing effects in AlGaAs during irradiation. Based on this, InGaAs/AlGaAs quantum-well lasers were fabricated and up to 49.3-nm-emission wavelength shift was observed in the proton-irradiated laser with no significant degradation in device characteristics. © 1999 American Institute of Physics.
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  • 8
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 1437-1439 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Arsenic ion implantation with thermal annealing was used to shorten the response times of GaAs-based saturable absorber structures. Ultrafast absorption bleaching measurements indicated that the recovery time was decreased with increasing the implantation dose. However, above a certain dose the recovery time increased again. This behavior was correlated with the microstructure of the residual implantation defects. © 1999 American Institute of Physics.
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  • 9
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 10-12 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Single high-energy (0.9 MeV) proton implantation and rapid thermal annealing was used to tune the spectral response of the quantum-well infrared photodetectors (QWIPs). In addition to the large redshift of the QWIPs' response wavelength after implantation, either narrowed or broadened spectrum was obtained at different interdiffusion extent. In general, the overall device performance for the low-dose implantation was not significantly degraded. In comparison with the other implantation schemes, this single high-energy implantation is the most effective and simple technique in tuning the wavelength of QWIPs, thus, to achieve the fabrication of multicolor detectors. © 2001 American Institute of Physics.
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  • 10
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 837-839 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The quality of spin-on silica films prebaked at different temperatures has been studied using Fourier transform infrared spectroscopy, spectroscopic ellipsometry, and P-etch [HF(40%):HNO3(70%):H2O=3:2:60] measurements. Low-temperature photoluminescence (PL) was performed on GaAs/AlGaAs quantum-well (QW) structures encapsulated by the same films. For all the prebaked films, not only the Si–O–Si peaks, but also OH-related peaks were detected in the IR spectra. After annealing at 950 °C for 60 s, almost all OH-related peaks disappeared. Spectroscopic ellipsometry modeling and P-etch measurements showed that the porosity of high-temperature (〉300 °C) baked samples was similar, and was significantly higher than the low-temperature (210 °C) baked sample. The same trend was observed in the PL energy shifts from the GaAs/AlGaAs QWs, indicating a direct correlation between the film quality and quantum-well intermixing. © 2000 American Institute of Physics.
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