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  • 1
    Electronic Resource
    Electronic Resource
    Electron transport in Sb-doped metalorganic epitaxial GaAs grown at moderate As-rich conditions (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 3566-3572 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The influence of antimony incorporation in GaAs metalorganic vapor phase epitaxial (MOVPE) layers has been investigated. The results obtained concern the behavior of the carrier concentration (n) and the mobility (μ) developed from Hall effect measurements. In order to achieve a reliable quantitative interpretation the samples studied have been grown at a moderate V/III ratio which ensures n-type conductivity and does not favor SbGa heteroantisite defect formation. Three regions of specific influence of Sb doping on the electrical parameters have been distinguished. For Sb mole fraction in the input gas phase (MFTMSb) ranging between 0 and 6×10−6, n slightly decreases, while the mobility sharply increases compared with undoped layers. This is discussed in terms of electrically active and neutral As vacancies. The quantitative consideration of the scattering mechanism offers the possibility of correcting the compensation ratio in the undoped GaAs samples determined by commonly used procedures. The n and μ dependences at higher Sb doping have been related to residual amphoteric impurity redistribution between Ga and As sublattices. In the heavily doped region the effect of the charged Ga vacancies has been involved. It has been shown that the Sb incorporation in the optimum concentration limits leads to an improvement of the electrical characteristics of MOVPE GaAs layers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.357416
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  • 2
    Electronic Resource
    Electronic Resource
    Elimination of nonuniformities in thick GaN films using metalorganic chemical vapor deposited GaN templates (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 90 (2001), S. 6011-6016 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Thick hydride vapor phase epitaxial GaN layers are grown on metalorganic chemical vapor deposited GaN template layers as well as directly on sapphire, with the aim of investigating the effect of the template on the strain relaxation and spatial distribution of free carriers in the overgrown GaN films. Spatially resolved cross-sectional micro-Raman spectroscopy, cathodoluminescence, and transmission electron microscopy show improved crystalline quality for growth on metalorganic chemical vapor deposited GaN templates. The highly doped and highly defective near-substrate layer composed of columnar domains, typically present in hydride vapor phase epitaxial GaN films grown directly on sapphire, is absent in the layers grown on templates. Consequently, this results in elimination of the nonuniformities of free electron distribution, a lower residual free carrier concentration (〈1017 cm−3), and improved strain relaxation. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1415363
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of Si doping of metalorganic chemical vapor deposition-GaN templates on the defect arrangement in hydride vapor phase epitaxy-GaN overgrown layers (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 5729-5732 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Two different types of dislocation arrangements have been observed in hydride vapor-phase epitaxial GaN films grown on sapphire substrates using both undoped and Si-doped GaN templates grown by metalorganic chemical vapor deposition: (i) predominantly straight threading dislocations parallel to the [0001] direction in the layer grown on an undoped template, and (ii) a network of interacting dislocations of edge, screw, and mixed character in the layer grown on a Si-doped template. The two types of defect distribution result in essentially different surface morphologies, respectively: (i) low-angle grain boundaries formed by pure edge dislocations around spiral grown hillocks, and (ii) smooth surface intersected by randomly distributed dislocations. The Si doping of the GaN templates was found to enhance defect interaction in the templates and to enable a reduction of the dislocation density in the overgrown thick GaN films, although it does not lead to an improvement of the overall structural properties of the material. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1318366
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  • 4
    Electronic Resource
    Electronic Resource
    Behavior of an EL5-like defect in metalorganic vapor-phase epitaxial GaAs:Sb (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 6170-6173 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An EL5-like trap in metalorganic vapor-phase epitaxially grown GaAs:Sb has been detected by deep-level transient spectroscopy. The trap behavior has been investigated by changing the growth conditions—the V/III ratio and the level of isoelectronic doping with Sb. It has been found that the activation energy of the EL5-like trap changes from Ec−0.43 eV in the undoped GaAs to Ec−0.35 eV in highly Sb-doped GaAs. It has been observed that the EL5 trap concentration increases with increasing the [AsH3] partial pressure in the undoped material, whereas it decreases with Sb doping in correlation with EL2 kinetic decrease. The results obtained suggest that the complex defect VGaAsi can be a possible candidate for the origin of the EL5-like trap.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.355184
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  • 5
    Electronic Resource
    Electronic Resource
    Misfit defect formation in thick GaN layers grown on sapphire by hydride vapor phase epitaxy (2002)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 80 (2002), S. 1550-1552 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The nucleation and microstructure of large-scale columnar domains present in hydride vapor phase epitaxial (HPVE)-GaN layers grown directly on sapphire have been studied using cathodoluminescence and transmission electron microscopy. The domains are distributed in a quasicontinuous layer close to the GaN/sapphire interface. The domain boundaries are found to be associated with stacking mismatch defects. They are initiated at steps on the sapphire surface and are formed between nucleation islands growing on adjacent terraces. The formation of these domains in the initial stages of HVPE-GaN heteroepitaxial growth is proposed to play an important role in the strain relaxation mechanism. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1455698
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  • 6
    Electronic Resource
    Electronic Resource
    Interface structure of hydride vapor phase epitaxial GaN grown with high-temperature reactively sputtered AlN buffer (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 1860-1862 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Thick hydride vapor phase epitaxy GaN layers have been grown on a-plane sapphire using high-temperature ion-assisted reactively sputtered AlN as a buffer layer. Transmission electron microscopy and atomic force microscopy were carried out to study the formation of the two interfaces sapphire/AlN and AlN/GaN, and their influence on the microstructure of both the buffer layer and the main GaN layer. It was demonstrated that the high-temperature reactively sputtered buffer layer provides a good alternative for hydride vapor phase epitaxy growth of GaN layers. In particular, the buffer promotes a specific interface ordering mechanism different from that observed on low-temperature buffers. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.126192
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  • 7
    Electronic Resource
    Electronic Resource
    Time-resolved spectroscopy of strained GaN/AlN/6H–SiC heterostructures grown by metalorganic chemical vapor deposition (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 1062-1064 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Temperature-dependent time-resolved photoluminescence measurements were performed on GaN film/AlN buffer/6H–SiC substrate heterostructures grown by metalorganic chemical vapor deposition. The overlying GaN layers were under tension, as estimated from the free A exciton (FEA) position. The recombination lifetimes were determined for the FEA and for the neutral-donor-bound exciton (D0X). We observed that the recombination lifetime for the FEA has the same value of 40–50 ps in all the layers, whereas the recombination time for the D0X varies for different samples. We observed that the recombination lifetimes for D0X have a clear dependence on the position of FEA, i.e., the recombination lifetime increases with decreasing strain in the layers. We discuss the results in term of the hole states involved in the donor-bound exciton recombination. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1350421
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  • 8
    Electronic Resource
    Electronic Resource
    Mass transport growth and optical emission properties of hydride vapor phase epitaxy GaN (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 4130-4132 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The optical emission properties of mass-transport regions of GaN grown by hydride vapor phase epitaxy are studied by cathodoluminescence imaging and spectroscopy. A strong donor–acceptor pair emission is observed from the mass-transport regions. Spatially resolved cathodoluminescence reveals a strong intensity contrast between the exciton and donor–acceptor bands from mass-transport and nontransport regions. Focused Auger electron and x-ray photoelectron spectroscopies were employed to investigate the impurity incorporation in the different regions. A preferential moderate increase of residual impurity incorporation or redistribution in mass-transport regions is suggested to be responsible for the observed change of the dominant radiative mechanism. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1381421
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  • 9
    Electronic Resource
    Electronic Resource
    Deformation potentials of the E1(TO) mode in AlN (2002)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 80 (2002), S. 2302-2304 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The deformation potentials of the E1(TO) mode in AlN are experimentally determined by combining infrared reflection spectroscopy and x-ray diffraction measurements and using a reported value of the Raman-stress factor for hydrostatically stressed bulk AlN. The deformation potentials are found to strongly depend on published stiffness constants of AlN. A comparison with earlier theoretically calculated values of the deformation potentials is made.© 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1465105
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  • 10
    Electronic Resource
    Electronic Resource
    Bound exciton dynamics in GaN grown by hydride vapor-phase epitaxy (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 4124-4126 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Temperature-dependent time-resolved photoluminescence measurements were performed on thick GaN layers grown by hydride vapor-phase epitaxy on Al2O3 substrates. Radiative lifetimes were determined for the neutral-donor–bound exciton with position at 3.478 eV and for two neutral-acceptor–bound excitons at 3.473 and 3.461 eV. We report a value of 3600 ps for the radiative lifetime of the acceptor–bound exciton transition at 3.461 eV. The dominant mechanism responsible for the nonradiative recombination of the bound excitons is shown to be connected with dissociation of the bound excitons into free excitons. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.125557
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