Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 11
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 3001-3011 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Secondary ion mass spectrometry has become the preferred tool for impurity profiling primarily due to its excellent depth resolution and high detection sensitivity. Prerequisite in obtaining high detection sensitivity for positive secondary ions is the use of oxygen as primary ions. This leads to a high degree of oxidation of the sample surface, which is essential for a high secondary ion ionization efficiency. Unfortunately, this oxygen bombardment not only leads to the transformation of the original target surface into an oxidized layer but, as the latter requires a certain fluence before stationary state is reached, inherently causes some nonlinearities and transients in the secondary ion signal and the fluence-eroded depth relation. In this work a computer code implantation, sputtering, replacement/relocation, and diffusion (ISRD) has been optimized to predict the compositional changes of the sample surface (or altered layer formation), the sputter yields and the surface regression as a result of the interaction of oxygen beams with Si-targets. This article describes a careful reevaluation of the previously used version of ISRD (and the parameters contained in the program) in order to obtain a systematic agreement with experimental data on sputter yields, altered layer formation, and surface recession, and with other theoretical predictions. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 178-182 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Gallium nitride layers grown by molecular beam epitaxy on c axis oriented sapphire substrates were implanted with 180 keV magnesium ions with ion doses between 1×1014 and 1×1016 cm−2. The implantation induced defect states were investigated by temperature dependent conductivity (TDC) as well as by thermal and optical admittance spectroscopy (TAS, OAS) measurements. Dominant carrier emissions having thermal activation energies between 360 and 800 meV were found in TAS and TDC. These states are assigned to implantation induced electron traps since they do not appear in the nonimplanted reference sample. Defect states with similar transition energies were also observed in OAS resulting in an enhancement of defect-to-band transitions in the near band-gap region around 3.45 eV, in the blue band around 3.0 eV, as well as in the midgap range for photon energies between 2.5 and 1.80 eV, respectively. In addition, new transitions were found at 2.1 and 1.95 eV. Furthermore, transitions from implantation induced shallow states were observed, i.e., the magnesium acceptor as well as a new donor level at about 70 meV, tentatively discussed as nitrogen vacancy. The critical ion dose for amorphization was determined to be between 5×1015 and 1×1016 Mg+ cm−2 using x-ray diffraction. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 2032-2034 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Optical transitions between the bands and electronic states in n-type GaN layers grown by molecular beam epitaxy on sapphire substrates using an electron cyclotron resonance (ECR) or a radio frequency (rf) nitrogen plasma source were investigated by means of optical admittance spectroscopy. The spectra of all layers similarly consist of a band gap region, a blue and a yellow band, and several defect-to-band transitions. However, in rf grown layers distinct transitions are separable, whereas ECR grown samples reveal broad bands, originating from potential fluctuations due to structural inhomogeneities induced by the ECR source. A defect at 0.82 eV is found characteristic for all ECR samples. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 1424-1426 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: SiC/GaN p-n and n-n heterostructures grown by low pressure chemical vapor deposition were investigated using thermal admittance spectroscopy. Different kinds of defects were isolated and located. Evidence of a distribution of defects at the p-SiC/n-GaN interface is given as having thermal activation energies of (87±3) meV at 5 V and (72±4) meV at 8 V bias. Additionally, three bulk defects with activation energies between 155 and 175 meV were found. By comparison with admittance spectra of the p-type SiC substrate, one level was identified as Al acceptor in SiC, whereas the other defects are electron traps in the GaN layer. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 77 (2000), S. 546-548 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In GaN layers grown by molecular beam epitaxy and metalorganic vapor phase epitaxy on c-axis oriented sapphire, a defect-to-band transition at a photon energy of 0.44 eV was found by optical admittance spectroscopy. This transition was investigated as a function of temperature and modulation frequency. The height of the corresponding optical admittance peak shows a thermally activated quenching with an activation energy of 0.4±0.1 eV caused by a thermal carrier emission from the same defect state to the conduction band at higher temperatures. Based on this thermal quenching, the 0.44 eV level is assigned to an electron trap located in the upper half of the gap. The spectral photoionization cross section was determined, resulting in a photoionization energy at 80 K estimated to be below 0.425 eV. The omnipresence of the 0.44 eV electron trap in GaN layers grown by various epitaxial techniques and in different reactors implicates its intrinsic nature. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 16
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 2040-2043 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Nominally undoped GaN layers grown by molecular beam epitaxy (MBE) and having resistivities between 105 and 107 Ω were investigated with temperature- and frequency-dependent admittance spectroscopy. The advantage of these measurement methods is shown in terms of the formation of Schottky contacts on high-resistivity GaN layers. The space-charge region, which is needed for detection of deep defects exists at low frequencies only and, therefore, deep level transient spectroscopy (DLTS) measurements fail for this material. Two deep defect levels were identified in MBE-grown GaN layers. The thermal activation energies are (0.45±0.04) and (0.63±0.04) eV, respectively. These deep traps are well known from DLTS and thermal stimulated conductivity measurements in metalorganic vapor phase epitaxy and hydride vapor phase epitaxy-grown GaN. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Optics Communications 18 (1976), S. 559-562 
    ISSN: 0030-4018
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Tetrahedron Letters 7 (1966), S. 2707-2710 
    ISSN: 0040-4039
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Tetrahedron Letters 6 (1965), S. 1127-1129 
    ISSN: 0040-4039
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 20
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Solid State Communications 87 (1993), S. 763-765 
    ISSN: 0038-1098
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...