ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
    Temperature dependence of the Γ8v-Γ6c gap of GaAs (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 2742-2747 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The photoluminescence (PL) peak positions of the ground state heavy and light-hole excitons on high-quality Molecular Beam Epitaxy grown GaAs/AlxGa1−xAs (x=0.3 and 1) multiquantum-well structures have been experimentally determined in the temperature range 4.2≤T≤340 K. Using these values and the well-known low-temperature energy of the GaAs Γ8V-Γ6C gap [EgΓ(GaAs,T=0 K)=1.5192 eV], we propose the temperature dependence to be EgΓ(GaAs,T)= 1.5192+5.16×10−5×T−1.99×10−6×T2 +2.60×10−9×T3 (EgΓ in eV). The nearly linear variation of EgΓ(GaAs,T) versus the temperature in the range 170 K≤T≤340 K can be approximated by a coefficient (dEgΓ/dT)=−4.4×10−4 eV/K, in excellent agreement with theoretical predictions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354674
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Thermal conversion of n-type GaAs:Si to p type in excess arsenic vapor (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 3887-3891 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Annealing in excess arsenic vapor at 650 °C introduces thermal conversion of n-type Si-doped GaAs samples (n = 1.3 × 1018 cm−3) into p type. The observations are made by current-voltage and electron-beam induced current measurements. The donor concentration on the n side near the junction decreases after annealing. We present a comparison between the photoluminescence spectra of samples annealed under different conditions and an analysis of depth profile of the photoluminescence spectra. Our results underline the important role of gallium vacancies and gallium vacancy-silicon donor complex in the thermal conversion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.349196
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Self-interstitial mechanism for Zn diffusion-induced disordering of GaAs/AlxGa1−xAs (x=0.1−1) multiple-quantum-well structures (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 3769-3781 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: GaAs/AlxGa1−xAs multiple-quantum-well (MQW) structures with identical well thicknesses but with different Al contents x in the barrier (x≈0.1, 0.2, 0.45, and 1) were grown by molecular-beam epitaxy to study the impurity-induced disordering mechanism. The disordering of the structures is observed directly by transmission electron microscopy on cleaved wedges of the sample, by the secondary electron imaging mode of scanning electron microscopy, and by secondary-ion-mass spectroscopy after Zn diffusions at 575 °C during different times (1, 4, 9, and 16 h). The results show that the totally and partially disordered regions are always behind the Zn diffusion front. The partially disordered extent depends on x. As x increases, the disordering rate increases due to the increase in Zn diffusivity. The effect of high Zn concentration is investigated by photoluminescence and by Raman scattering measurements. The systematical analysis of the photoluminescence spectra of the MQW structures diffused for different times and of the photoluminescence spectra taken on different depths below the sample surface makes it possible to describe the physical processes occurring during Zn diffusion. The column-III vacancies are created at the sample surface. They diffuse into the bulk of the sample where they are filled by other defects. Using the x-ray-diffraction technique, an expansion of the lattice constant in the region behind the Zn diffusion front was observed. This is due to a supersaturation of column-III interstitials. During the incorporation of Zn into the crystal lattice, column-III interstitials are generated. These interstitials could be responsible for the enhancement of the Al-Ga interdiffusion. The important role of the electric field at the p-n junction formed by Zn diffusion is discussed. The negatively charged column-III vacancies and the positively charged column-III interstitials are confined, respectively, on the n and p sides of the p-n junction. The results give evidence for the self-interstitial mechanism of Zn diffusion-induced disordering in GaAs/AlGaAs MQW structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352883
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Cathodoluminescence and photoluminescence studies of dislocations in GaAs/AlGaAs quantum wells (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 1997-2003 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The optical properties of low pressure metal organic vapor deposition grown GaAs/AlxGa1−xAs (x=0.5) single quantum well structures (SQW) with grown-in dislocations (GD) were studied by low temperature cathodoluminescence (CL) and photoluminescence (PL). High luminescence efficiency around the GD was observed and attributed to impurity decoration. CL spectra show a region surrounding the GD that consists of Si impurities and native defects in the SQW and barrier layers. The diameter of this region was found to be in the order of 1 μm using spectrally resolved CL micrographs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354761
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    The electro-optic coefficients of GaAs: Measurements at 1.32 and 1.52 μm and study of their dispersion between 0.9 and 10 μm (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 2821-2825 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The linear (r41) and quadratic (R11 and R12) electro-optic coefficients of GaAs have been measured at the wavelengths 1.32 and 1.52 μm using single-mode AlGaAs/GaAs strip-loaded waveguides. The results are r41=−(1.54±0.08)×10−10 cm/V, R11=−(9.3±2.8)×10−17 cm2/V2 and R12=−(5.1±l.9)×10−17 cm2/V2 at 1.32 μm and r41=−(1.50±0.08)×10−10 cm/V, R11=−(3.2±2.3)×10−17 cm2/V2 and R12=−(5.1±2.6)×10−17 cm2/V2 at 1.52 μm. These results, together with those previously measured at different wavelengths, are compared with published theoretical models. The linear electro-optic coefficient r41 is slightly dispersive near the band gap and roughly constant for longer wavelengths, in good agreement with the models. The quadratic electro-optic coefficients drop rapidly with increasing wavelength, in good agreement with a model based on electroabsorption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.351011
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Luminescence peculiarities on (AlGa)As single quantum well (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 1552-1554 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: This paper reports on single quantum well characterization by means of luminescence excited with a laser (photoluminescence) and an electron beam (cathodoluminescence) at liquid helium temperatures. Small quantum well regions with smaller confinement were observed. They seem to be associated with dislocations originated at the substrate. The observed shift of the X(e-hh) peak position versus the excitation level can be explained by luminescence generation in different lateral regions of the quantum well.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.351231
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Role of point defects in the silicon diffusion in GaAs and Al0.3Ga0.7As and in the related superlattice disordering (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 2225-2237 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The mechanism of silicon diffusion in GaAs, Al0.3Ga0.7As, and the silicon diffusion-induced layer disordering of multiquantum wells have been studied by photoluminescence, secondary-ion-mass spectroscopy, and transmission electron microscopy across a corner of a wedge-shaped sample. The diffusion source was a grown in highly Si-doped layer. The main photoluminescence properties of point defects in GaAs and Al0.3Ga0.7As are reviewed to interpret the experimental data. The depth profile of the photoluminescence allows the spatial correlation between the luminescence spectra and the Si concentration profile obtained from secondary-ion-mass-spectroscopy measurements. On the basis of the photoluminescence results, the physical processes occurring during the Si diffusion are discussed. Frenkel defects (pairs of element-III vacancies and interstitials) are generated in the highly Si-doped region. The element-III interstitials rapidly diffuse towards the surface where they react with the element-III vacancies generated at the surface when annealing is performed in an external As pressure. This induces a supersaturation of element-III vacancies in the Si-doped region which drives the Si diffusion. Annealing in vacuum reduces the oversaturation of element-III vacancies and, hence, reduces the Si diffusion. A domination of the Si donor–element-III vacancy complex emission band was found in the spectra taken in the Si-diffused region. This gives evidence for the vacancy-assisted mechanism in the Si diffusion and in the impurity-induced disordering.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.351120
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    A model for the Zn diffusion in GaAs by a photoluminescence study (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 7585-7593 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: To study the mechanism of zinc diffusion in GaAs, we diffused zinc from a ZnAs2 source into Si-doped GaAs samples (n ≈ 1.3 × 1018 cm−3) at different temperatures (from 575 °C up to 700 °C) in sealed evacuated quartz tubes. The samples are characterized by the depth profile of the photoluminescence at different temperatures. The photoluminescence spectra show characteristic emission associated to deep levels of gallium and arsenic vacancies. A detailed analysis of the spectra demonstrates the role played by vacancies in the Zn diffusion process. The spatial correlation between the luminescence spectra and the Zn concentration obtained from secondary ion mass spectroscopy measurements has been demonstrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.347527
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Effects of background n- and p-type doping on Zn diffusion in GaAs/AlGaAs multiple-quantum-well structures (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 259-266 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effects of background n- and p-type doping on Zn diffusion in GaAs/AlGaAs multilayered structures are investigated by secondary-ion-mass spectrometry and photoluminescence measurements. Zn diffusions are performed at 575 °C into Si-doped, Be-doped, and Si/Be-codoped identical GaAs/Al0.2Ga0.8As multiple-quantum-well structures. The results obtained by secondary-ion-mass spectrometry show that the Zn diffusion induces an enhancement of Be out-diffusion and the disordering of all structures. The effective Zn diffusivity and the disordering rate are increased by Be doping and reduced by Si doping. Photoluminescence measurements give information about the reactions of different point defects during the diffusion process. Before Zn diffusion, the Si-doped structures contain a high concentration of column-III vacancies, whereas As vacancies are the dominant defects in the Be-doped structures. After Zn diffusion, we observe a reduction of column-III vacancy concentration in Si-doped structures and an increase of column-III interstitial concentration in Be-doped structures. A model based on the "kick-out" mechanism of Zn diffusion is proposed to explain our observations. The supersaturation of column-III interstitials behind the Zn diffusion front is responsible for the enhancements of Al–Ga interdiffusion and Be out-diffusion. The effective Zn diffusivity is controlled by the background donor or acceptor concentration ahead of the Zn diffusion front and by the concentration of column-III interstitials behind the Zn diffusion front. For Be-doped structures, the increase in the background acceptor concentration and the supersaturation of column-III interstitials in the Zn-diffused region results in an enhancement of the Zn diffusivity. For Si-doped structures, the effective Zn diffusivity decreases with increasing background donor concentration. Moreover, the concentrations of column-III interstitials and column-III vacancies in the Zn-diffused region are reduced due to their mutual annihilation, leading to a retardation of Zn diffusion. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.370724
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Capacitance-voltage profiling of quantum well structures (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 7005-7013 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Capacitance-voltage (C-V) analysis of high quality MBE grown quantum well samples shows that carrier distributions are averaged over the scale of the Debye length. This averaging process results in strongly temperature dependent C-V-deduced doping distributions that can be very different from the actual ones. The doping distribution of the structure is obtained by fitting numerically simulated curves to the measured C-V curves and doping profiles, respectively. Although the calculations do not take quantum size effects into account they show good agreement with the measured data. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.361466
    Location Call Number Expected 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...