Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Nitrogen donors in 4H-silicon carbide (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 3332-3338 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Hall-effect and infrared-absorption measurements are performed on n-type 4H-SiC samples to investigate the energy positions of the ground state and the excited states of the nitrogen donor in the 4H polytype of silicon carbide. Two electrically active levels (Hall effect) and three series of absorption lines (infrared spectra) are assigned to two nitrogen donor species which substitute on the two inequivalent lattice sites (h,k) in 4H-SiC. Valley-orbit splitting of the ground-state level of the nitrogen donors on hexagonal sites (h) is found to be equal to ΔEvo(h)=7.6 meV. It is shown that the energy position of excited states of both nitrogen donors can be calculated by the effective-mass approximation by assuming anisotropic effective masses m⊥=0.18m0 and m(parallel)=0.22m0. The influence of the two inequivalent lattice sites on the values of ionization energy and valley orbit splitting of the nitrogen donor ground-state levels is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352983
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Thermal donor formation and annihilation at temperatures above 500 °C in Czochralski-grown Si (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 3561-3568 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Thermal donors (TDs) are generated in Czochralski (CZ)-grown silicon by heat treatments around 450 °C. They form several individual effective-mass-like donors with slightly different ionization energies and act as double donors (TDx0,TDx+). Heat treatments at elevated temperatures (e.g., 〉500 °C) lead to a competition of the formation and the annihilation of TDs. We studied the formation and the annihilation of TDs in the temperature range between 520 and 700 °C. CZ-grown Si samples with an initial total TD concentration of ∼5×1015 cm−3 were employed to study the annihilation of TDs. The number of interstitial oxygen atoms generated per annihilated TD center depends on the temperature and ranges from 4 to 24. For the temperature range investigated the activation energy for thermal annihilation of TDs was determined to be 2.5±0.4 eV. The same CZ-Si material but with an initial TD concentration of ∼2×1013 cm−3 was used to study the formation of TDs. During annealing, the concentrations of individual TDs reach equilibrium concentrations, which depend on the temperature of the final annealing step and the total oxygen concentration. We demonstrate that a model in which the individual TDx centers are represented by oxygen clusters of different sizes consistently explains our experimental data. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.368586
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Hall-effect analysis of GaN films grown by hydride vapor phase epitaxy (1998)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 72 (1998), S. 1214-1216 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Hall-effect measurements were conducted on unintentionally doped n-type GaN films grown on sapphire substrates by hydride vapor phase epitaxy. Film nucleation involved either a GaCl or ZnO pretreatment. Variable temperature Hall-effect measurements reveal a dependence of both the electron concentration and the Hall mobility on film thickness. We demonstrate that this dependence is indicative of a nonuniform distribution of electrically active defects. For GaCl-pretreated sapphire the presence of a highly conductive, 200-nm-thick near-interface layer is likely to account for the observed phenomena. For ZnO-pretreated sapphire the Hall-effect data clearly indicate a continuous reduction of the defect density with increasing film thickness. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.121017
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Activation energies of Si donors in GaN (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 3144-3146 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The electronic properties of Si donors in heteroepitaxial layers of GaN were investigated. The n-type GaN layers were grown by metalorganic chemical vapor deposition and either intentionally doped with Si or unintentionally doped. The samples were evaluated by variable temperature Hall effect measurements and photoluminescence (PL) spectroscopy. For both types of samples the n-type conductivity was found to be dominated by a donor with an activation energy between 12 and 17 meV. This donor is attributed to Si atoms substituting for Ga in the GaN lattice (SiGa). The range of activation energies is due to different levels of donor concentrations and acceptor compensation in our samples. The assignment of a PL signature to a donor–acceptor pair recombination involving the Si donor level as the initial state of the radiative transition yields the position of the optical Si donor level in the GaN bandgap at ∼Ec–(22±4) meV. A deeper donor level is also present in our GaN material with an activation energy of ∼34 meV which is tentatively assigned to oxygen donors substituting for nitrogen (ON). © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.115805
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Deep level defects in Mg-doped, p-type GaN grown by metalorganic chemical vapor deposition (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 3470-3472 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Deep level defects in Mg-doped, p-type GaN were characterized by deep level transient spectroscopy (DLTS) and photoemission capacitance transient spectroscopy (ODLTS). The measurements were conducted on n+-p junction diodes grown by metalorganic chemical vapor deposition. DLTS revealed discrete deep levels in the lower half of the band gap with activation energies for hole emission of 0.21, 0.39, and 0.41 eV. While DLTS is able to detect deep levels only in the proximity of the valance band edge in p-type, wide band-gap semiconductors, ODLTS enables detection of deep levels throughout the band gap of GaN. The ODLTS spectrum of Mg-doped, p-type GaN is dominated by a deep level with an optical threshold energy for photoionization of ∼1.8 eV. This deep level, which appears to be energetically located near midgap is present in the highest concentration (∼2.4×1015 cm−3) among the deep levels detected in our GaN material. None of the detected deep levels is present in sufficient concentration to significantly compensate the shallow acceptor dopant in our Mg-doped, p-type GaN. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.116075
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Photoemission capacitance transient spectroscopy of n-type GaN (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 1340-1342 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Electronic defects in n-type GaN were characterized by photoemission capacitance transient spectroscopy. Conventional deep level transient spectroscopy is of limited use in semiconductors with wide band gaps (e.g., 3.4 eV for GaN at 300 K) because it utilizes thermal energy for charge emission which restricts the accessible range of bandgap energies to within ∼0.9 eV of either band edge, for practical measurement conditions. For electron photoemission to the conduction band, four deep levels were detected at optical threshold energies of approximately 0.87, 0.97, 1.25, and 1.45 eV. It is suggested that the above photodetected deep levels may participate in the 2.2 eV defect luminescence transitions, which are also demonstrated for our material. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.113235
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Deep level defects in n-type GaN (1994)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 65 (1994), S. 463-465 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In n-type GaN grown by metalorganic chemical vapor deposition two new electronic defects were detected and characterized by deep level transient spectroscopy (DLTS). Schottky-barrier diodes with Ohmic back contacts and low series resistance were fabricated in GaN layers grown on sapphire. The diodes display well behaved current-voltage and capacitance-voltage characteristics and permit unambiguous DLTS evaluation. The new deep levels display thermal activation energies for electron emission of 0.49 and 0.18 eV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.112337
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Hydrogen passivation of Mg acceptors in GaN grown by metalorganic chemical vapor deposition (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 2666-2668 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effects of the deliberate hydrogenation of GaN were investigated for heteroepitaxial layers grown by metalorganic chemical vapor deposition. The GaN layers were either Mg-doped, p-type after thermal activation, or Si-doped, n type. Elemental depth profiles from secondary ion mass spectroscopy reveal a striking contrast after a deuteration at 600 °C: the deuterium concentration in Mg-doped GaN is ∼1019 cm−3 while there is no detectable deuterium incorporation in the n-type material. Variable temperature Hall effect measurements provide the most direct evidence to date for Mg–H complex formation with the decrease in the hole concentration upon hydrogenation accompanied by an increase in the hole Hall mobility. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.114330
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Homoepitaxy of GaN on polished bulk single crystals by metalorganic chemical vapor deposition (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 917-919 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Bulk single crystals of GaN were used for epitaxial growth of GaN by metalorganic chemical vapor deposition. Photoluminescence (at 2 K) from polished substrates yields a broad near-band-edge emission band centered at 3.32 eV and the commonly observed yellow luminescence band. In contrast, the epitaxial layer displays a strong, sharp bound exciton line at 3.458 eV and a weak yellow band. Transmission electron microscopy reveals a sharp, planar interface between substrate and epilayer: The substrate contains small Ga inclusions, and the epilayer consists of less than 108 dislocations per cm2, mostly in the form of dislocation loops, which originate at the interface. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.116230
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Spatial distribution of the luminescence in GaN thin films (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 57-59 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The spatial dependence of the luminescence intensities at the band edge (364 nm) and at the "yellow'' defect-band (centered at 560 nm) regions for epitaxial GaN films have been studied using cathodoluminescence microscopy at room temperature. The films were grown by metalorganic chemical vapor deposition on (0001) sapphire substrates and were not intentionally doped. Significant nonuniformities in the band-to-band and in the yellow band emissions were observed. Yellow luminescence in small crystallites appears to originate from extended defects inside the grains and at low-angle grain boundaries. The size of band-to-band emission sites correlates with low-angle grain sizes observed by transmission electron microscopy. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.116756
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...