@article{WuBeckerWaagetal.1993,
  author    = {Wu, Y. S. and Becker, Charles R. and Waag, A. and Bicknell-Tassius, R. N. and Landwehr, G.},
  title     = {Removal of oxygen and reduction of carbon contamination on (100) Cd\(_{0.96}\)Zn\(_{0.04}\)Te},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-38014},
  year      = {1993},
  abstract  = {No abstract available},
  language  = {en}
}
@article{HeBeckerBicknellTassiusetal.1993,
  author    = {He, L. and Becker, Charles R. and Bicknell-Tassius, R. N. and Scholl, S. and Landwehr, G.},
  title     = {Molecular beam epitaxial growth and evaluation of intrinsic and extrinsically doped (100) Hg\(_{0.8}\)Cd\(_{0.2}\)Te on (100) Cd\(_{0.96}\)Zn\(_{0.04}\)Te},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37885},
  year      = {1993},
  abstract  = {No abstract available.},
  language  = {en}
}
@article{KrausRegnetBeckeretal.1992,
  author    = {Kraus, M. M. and Regnet, M. M. and Becker, Charles R. and Bicknell-Tassius, R. N. and Landwehr, G.},
  title     = {Comparison of band structure calculations and photoluminescence experiments on HgTe/CdTe superlattices grown by molecular beam epitaxy},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37878},
  year      = {1992},
  abstract  = {We have grown HgTe/CdTe superlattices by molecular beam epitaxy; barrier thicknesses were in the range from 15 to 91 {\AA} and the well thickness was maintained at a constant value of 30 {\AA}. The infrared photoluminescence was investigated by means of Fourier transform infrared spectroscopy in the temperature range from 4.2 to 300 K. All superlattices showed pronounced photoluminescence at temperatures up to 300 K. To gain more detailed insight into the band structure of the HgTe/CdTe superlattices, band structure calculations were performed. The concept of the envelope function approximation was followed. Employing the transfer matrix method, the calculations were completed taking into account an eight band k·p model. An important parameter in these calculations is the natural valence band offset (VBO) between the well and barrier materials. As a general trend, the value for the direct gap decreases with increasing VBO. The experimentally determined energies of the band gap are in reasonable agreement with the values obtained by the theoretical calculations. A comparison between theory and experiment shows that the observed transition energies are closer to calculations employing a large offset (350 meV) as opposed to a small VBO (40 meV).},
  language  = {en}
}
@article{WuBeckerWaagetal.1993,
  author    = {Wu, Y. S. and Becker, Charles R. and Waag, A. and Schmiedl, R. and Einfeldt, S. and Landwehr, G.},
  title     = {Oxygen on the (100) CdTe surface},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37869},
  year      = {1993},
  abstract  = {We have investigated oxygen on CdTe substrates by means of x-ray photoelectron spectroscopy (XPS) and reflection high-energy electron diffraction (RHEED). A Te oxide layer that was at least 15 A thick was found on the surface of as-delivered CdTe substrates that were mechanically polished. This oxide is not easily evaporated at temperatures lower than 350°C. Furthermore, heating in air, which further oxidizes the CdTe layer, should be avoided. Etching with HCI acid (15\% HCl) for at least 20 s and then rinsing with de-ionized water reduces the Te oxide layer on the surface down to 4\% of a monoatomic layer. However, according to XPS measurements of the 0 Is peak, 20\%-30\% of a monoatomic layer of oxygen remains on the surface, which can be eliminated by heating at temperatures ranging between 300 and 340 cC. The RHEED patterns for a molecular beam epitaxially (MBE)-grown CdTe film on a (lOO) CdTe substrate with approximately one monoatomic layer of oxidized Te on the surface lose the characteristics of the normal RHEED pattems for a MBE-grown CdTe film on an oxygen-free CdTe substrate.},
  language  = {en}
}
@inproceedings{BoegeSchaeferShanjiaetal.1994,
  author    = {Boege, P. and Sch{\"a}fer, H. and Shanjia, Xu and Xinzhang, Wu and Einfeldt, S. and Becker, Charles R. and Hommel, D. and Geick, R.},
  title     = {Improved conductivity-measurement of semiconductor epitaxial layers by means of the contactless microwave method},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37763},
  year      = {1994},
  abstract  = {Measurements and calculations of the scattering-characteristics of stratified lossy dielectric blocks completely filling a waveguide cross section are presented. The method is used for contactless conductivity measurements of MBE-grown II-VI semiconductor layers.},
  subject      = {Millimeterwelle},
  language  = {en}
}
@article{WuBeckerWaagetal.1991,
  author    = {Wu, Y.S. and Becker, Charles R. and Waag, A. and Kraus, M. M. and Bicknell-Tassius, R. N. and Landwehr, G.},
  title     = {Correlation of the Cd-to-Te ratio on CdTe surfaces with the surface structure},
  isbn      = {0163-1829},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37789},
  year      = {1991},
  abstract  = {We report here that reconstruction on (100), (1lIlA, and (1l1lB CdTe surfaces is either C(2X2), (2X2), and (l X I) or (2X I), (l X I), and (l X I) when they are Cd or Te stabilized, respectively. There is a mixed region between Cd and Te stabilization in which the reflected high-energy electron-diffraction (RHEED) patterns contain characteristics of both Cd- and Te-stabilized surfaces. We have also found that the Cd-to-Te ratio of the x-ray photoelectron intensities of their 3d\(_{3/ 2}\) core levels is about 20\% larger for a Cd-stabilized (1lIlA, (1lIlB, or (100) CdTe surface than for a Te-stabilized one. According to a simple model calculation, which was normalized by means of the photoelectron intensity ratio of a Cd-stabilized (lll)A and aTe-stabilized (1l1lB CdTe surface, the experimental data for CdTe surfaces can be explained by a linear dependence of the photoelectron-intensity ratio on the fraction of Cd in the uppermost monatomic layer. This surface composition can be correlated with the surface structure, i.e., the corresponding RHEED patterns. This correlation can in turn be employed to determine Te and Cd evaporation rates. The Te reevaporation rate is increasingly slower for the Te-stabilized (Ill) A, (l1l)B, and (100) surfaces, while the opposite is true for Cd from Cd-stabilized (Ill) A and (Ill)B surfaces. In addition, Te is much more easily evaporated from all the investigated surfaces than is Cd, if the substrate is kept at normal molecular-beam-epitaxy growth temperatures ranging from 2oo·C to 300 ·C.},
  subject      = {Festk{\"o}rperphysik},
  language  = {en}
}
@inproceedings{BicknellTassiusSchollBeckeretal.1992,
  author    = {Bicknell-Tassius, R. N. and Scholl, S. and Becker, Charles R. and Landwehr, G.},
  title     = {High magnetic field transport in II-VI heterostructures},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37797},
  year      = {1992},
  abstract  = {In the present work we report the results of magneto-transport measurements on some Hg-based li-VI semiconductor epitaxiallayers grown by molecular beam epitaxy. The transport measurement were carried out at temperatures in the range 0.4 - 4.2 K in magnetic fields up to 10.0 T. Further, we point out the necessity of using multicarrier models for data interpretation and show finally some Shubnikov-de-Haas results on sampies with high mobility carners.},
  language  = {en}
}
@article{GeisGeickBeckeretal.1977,
  author    = {Geis, G. and Geick, R. and Becker, Charles R. and Wagner, V.},
  title     = {Antiferromagnetic resonance in CoO/NiO mixed crystals},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-31239},
  year      = {1977},
  abstract  = {We have studied the lowest magnetic excitation of Ni\(_{1-x}\)Co\(_x\)O mixed crystals for 0.94 \(\leq\) x \(\leq\) 1. Together with previous results for 0.02 \(\leq\) x \(\leq\) 0.07 and neutron data for x = 0.14 and x = 0.30, the results are discussed by means of a model, especially the variation of AFMR frequency and preferred spin direction with Co concentration x.},
  language  = {en}
}
@article{WuBeckerWaagetal.1991,
  author    = {Wu, Y. S. and Becker, Charles R. and Waag, A. and Bicknell-Tassius, R. N. and Landwehr, G.},
  title     = {The effects of laser illumination and high energy electrons on molecular-beam epitaxial growth of CdTe},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-30795},
  year      = {1991},
  abstract  = {We report the results of a detailed investigation on the Te-stabilized (2 x 1) and the Cdstabilized c( 2 X 2) surfaces of ( 100) CdTe substrates. The investigation demonstrates for the first time that both laser illumination and, to a greater extent, high-energy electron irradiation increase the Te desorption and reduce the Cd desorption from ( 100) CdTe surfaces. Thus it is possible by choosing the proper growth temperature and photon or electron fluxes to change the surface reconstruction from the normally Te-stabilized to a Cd-stabilized phase.},
  language  = {en}
}
@article{XuShengGreineretal.1994,
  author    = {Xu, Shanjia and Sheng, Xinqing and Greiner, P. and Becker, Charles R. and Geick, R.},
  title     = {High-order finite-element analysis of scattering properties of II-VI semiconductor materials},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86283},
  year      = {1994},
  abstract  = {The sattering characteristics ot the n-VI semiconductors were analyzed by a method which combines the second-order finite-element method with the rigorous mode matching procedure. The method avolds the difficulty of solving the complex transcendental equation introduced in the multimode network method and calculates all the eigenvalues and eigenfunctions simultaneously which are needed for the mode matching treatment in the longitudinal direction. As a result, the whole solution procedure is significantly simplified. A comparison is given between the experimental data and the calculated results obtained with this analysis and tbe network method. Very good agreement has been achieved, the accuracy and efficiency of the present method are thus verified.},
  subject      = {Halbleiter},
  language  = {en}
}