@article{RoeschAtzmuellerSchaacketal.1994,
  author    = {R{\"o}sch, M. and Atzm{\"u}ller, R. and Schaack, G. and Becker, Charles R.},
  title     = {Resonant Raman scattering in a zero-gap semiconductor: Interference effects and deformation potentials at the E\(_1\) and E\(_1\) + \(\Delta_1\) gaps of HgTe},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-38062},
  year      = {1994},
  abstract  = {No abstract available},
  language  = {en}
}
@article{ZhangBeckerZhangetal.1994,
  author    = {Zhang, X. F. and Becker, Charles R. and Zhang, H. and He, L. and Landwehr, G.},
  title     = {Investigation of a short period (001) HgTe-Hg\(_{0.6}\)Cd\(_{0.4}\)Te superlattice by transmission electron microscopy},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-38029},
  year      = {1994},
  abstract  = {No abstract available},
  language  = {en}
}
@article{EinfeldtHeinkeBehringeretal.1994,
  author    = {Einfeldt, S. and Heinke, H. and Behringer, M. and Becker, Charles R. and Kurtz, E. and Hommel, D. and Landwehr, G.},
  title     = {The growth of HgSe by molecular beam epitaxy for ohmic contacts to p-ZnSe},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-38001},
  year      = {1994},
  abstract  = {The structural properties of HgSe grown by molecular beam epitaxy (MBE) are investigated for different lattice mismatches to the substrate and various growth conditions. The growth rate is shown to depend strongly on the growth temperature above lOO°C as well as on the Hg/Se flux ratio. It has been found that the crystalline perfection and the electrical properties are mainly determined by the layer thickness, especially for the growth on highly lattice mismatched substrates. Changes in the surface morphology are related to growth parameters. Differences between the electrical behavior of MBE-grown and bulk HgSe are discussed. The electrical properties of HgSe contacts on p-ZnSe are investigated as a function of different annealing procedures.},
  language  = {en}
}
@article{SchikoraHausleitnerEinfeldtetal.1994,
  author    = {Schikora, D. and Hausleitner, H. and Einfeldt, S. and Becker, Charles R. and Widmer, T. and Giftige, C. and Lischka, K. and von Ortenburg, M. and Landwehr, G.},
  title     = {Epitaxial overgrowth of II-VI compounds on patterned substrates},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37985},
  year      = {1994},
  abstract  = {The selected area epitaxial overgrowth of narrow gap HgTe as well as wide gap CdTe and ZnTe on CdTe/GaAs substrates, which had been structured by dry etching techniques, has been investigated. A plasma etching process using a barrel reactor with CH\(_4\)-CH\(_2\) gases has been employed to prepare stripes with a width of about 1 μm with anisotropic as well as isotropic etching profiles. It has been found, that the selected area HgTe overgrowth takes place with a high local selectivity to the low index planes of the patterned surface. In contrast, the selected area overgrowth of the wide gap CdTe and ZnTe is controlled by anisotropic growth kinetics provided that the substrate temperature is not lower than 220°C and the starting surface consists of well developed low index crystallographic planes.},
  language  = {en}
}
@article{ToenniesBacherForcheletal.1994,
  author    = {T{\"o}nnies, D. and Bacher, G. and Forchel, Alfred and Waag, A. and Litz, Th. and Hommel, D. and Becker, Charles R. and Landwehr, G. and Heuken, M. and Scholl, M.},
  title     = {Optical study of interdiffusion in CdTe and ZnSe based quantum wells},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37750},
  year      = {1994},
  abstract  = {No abstract available},
  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{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}
}
@article{BeckerHeEinfeldtetal.1993,
  author    = {Becker, Charles R. and He, L. and Einfeldt, S. and Wu, Y. S. and L{\´e}rondel, G. and Heinke, H. and Oehling, S. and Bicknell-Tassius, R. N. and Landwehr, G.},
  title     = {Molecular beam epitaxial growth and characterization of (100) HgSe on GaAs},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-50947},
  year      = {1993},
  abstract  = {In this paper, we present results on the first MBE growth of HgSe. The influence of the GaAs substrate temperature as well as the Hg and Se fluxes on the growth and the electrical properties has been investigated. It has been found that the growth rate is very low at substrate temperatures above 120°C. At 120°C and at lower temperatures, the growth rate is appreciably higher. The sticking coefficient of Se seems to depend inversely on the Hg/Se flux ratio. Epitaxial growth could be maintained at 70°C with Hg/Se flux ratios between lOO and ISO, and at 160°C between 280 and 450. The electron mobilities of these HgSe epilayers at room temperature decrease from a maximum value of 8.2 x 10^3 cm2 /V' s with increasing electron concentration. The concentration was found to be between 6xlO^17 and 1.6x10^19 cm- 3 at room temperature. Rocking curves from X-ray diffraction measurements of the better epilayers have a full width at half maximum of 5S0 arc sec.},
  subject      = {Physik},
  language  = {en}
}
@article{ShanjiaXinzhangBoegeetal.1993,
  author    = {Shanjia, Xu and Xinzhang, Wu and Boege, P. and Sch{\"a}fer, H. and Becker, Charles R. and Geick, R.},
  title     = {Scattering characteristics of 3-D discontinuity consisting of semiconductor sample filled in waveguide with gaps},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37964},
  year      = {1993},
  abstract  = {No abstract available},
  language  = {en}
}
@article{WaagHeinkeScholletal.1993,
  author    = {Waag, A. and Heinke, H. and Scholl, S. and Becker, Charles R. and Landwehr, G.},
  title     = {Growth of MgTe and Cd\(_{1-x}\)Mg\(_x\)Te thin films by molecular beam epitaxy},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37917},
  year      = {1993},
  abstract  = {We report on the growth of the compound semiconductor MgTe as weil as the ternary alloy Cd\(_{l-x}\)Mg, Te by molecular hcam cpitaxy. This is to our knowkdgc thc first time that this material has heen grown by any epitaxial technique. Bulk MgTe, which is hygroscopic, has a band gap of 3.0 eV and crystallizcs usually in thc wurtzite structure. Pseudomorphic films were grown on zincblende Cd Te suhstrates for a MgTe thickness helow a critical layer thickncss of approximately 500 nm. In addition, Cd\(_{l_x}\),Mg\(_x\)Te epilayers were grown with a Mg concentration between 0 and 68\%, which corresponds to a band gap betwcen 1.5 and 2.5 eV at room temperature. The crystalline quality of thc layers is comparabk to CdTc thin films as long as they are fully strained. The lauice constant of zincblende MgTe is slightly smaller than that of CdTe, and the lattice mismatch is as low as O.7\%. In addition highly n-type CdMgTe layers were fabricatcd by hromine doping. The tunability of the band gap as weil as the rather good laUice match with CdTc makes the matcrial interesting for optoelectronic device applications for the entire visible range.},
  language  = {en}
}
@article{HerrmannHappMoellmannetal.1993,
  author    = {Herrmann, K. H. and Happ, M. and M{\"o}llmann, K.-P. and Tomm, J. W. and Becker, Charles R. and Kraus, M. M. and Yuan, S. and Landwehr, G.},
  title     = {A new model for the absorption coefficient of narrow gap (Hg,Cd)Te that simultaneously considers band tails and band filling},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37894},
  year      = {1993},
  abstract  = {A semiempirical model is presented that correlates the broadening of the absorption edge with both transitions below the energy gap and with transitions by the Kane band model. This model correctly fits both the absorption and luminescence spectra of narrow-gap (Hg,Cd)Te samples that have been grown by the traveling heater method as well as by molecular-beam epitaxy. The accuracy of the band-gap determination is enhanced by this model.},
  language  = {en}
}
@article{WuBeckerWaagetal.1993,
  author    = {Wu, Y. S. and Becker, Charles R. and Waag, A. and von Schierstedt, K. and Bicknell-Tassius, R. N. and Landwehr, G.},
  title     = {Surface sublimation of zinc blende CdTe},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37829},
  year      = {1993},
  abstract  = {The surface sublimation of Cd and Te atoms from the zinc blende (111)A CdTe surface has been investigated in detail by reflection high energy electron diffraction and x-ray photoelectron spectroscopy. These experiments verify that Te is much easier to evaporate than Cd. The experimental value for the Te activation energy from a Te stabilized (111)A CdTe surface is 1.41 ±0.1O eV, which is apparently inconsistent with recent theoretical results.},
  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 of (100) Hg\(_{0.8}\)Cd\(_{0.2}\)Te on Cd\(_{0.96}\)Zn\(_{0.04}\)Te},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-38044},
  year      = {1993},
  abstract  = {No abstract available},
  language  = {en}
}
@article{KrausBeckerScholletal.1993,
  author    = {Kraus, M. M. and Becker, Charles R. and Scholl, S. and Wu, Y. S. and Yuan, S. and Landwehr, G.},
  title     = {Infrared photoluminescence on molecular beam epitaxially grown Hg\(_{1-x}\)Cd\(_x\)Te layers},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-38053},
  year      = {1993},
  abstract  = {No abstract available},
  language  = {en}
}
@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{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}
}
@article{BeckerHeRegnetetal.1993,
  author    = {Becker, Charles R. and He, L. and Regnet, M. M. and Kraus, M.M. and Wu, Y. S. and Landwehr, G. and Zhang, X. F. and Zhang, H.},
  title     = {The growth and structure of short period (001) Hg\(_{1-x}\)Cd\(_x\)Te-HgTe superlattices},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37858},
  year      = {1993},
  abstract  = {Molecular beam epitaxially grown short period (001) Hg\(_{1_x}\)Cd\(_x\)Te-HgTe superlattices have been systematically investigated. Several narrow well widths were chosen, e.g., 30, 35 and 40 {\AA}, and the barrier widths were varied between 24 and 90 {\AA} for a particular well width. Both the well width and the total period were determined directly by means of x-ray diffraction. The well width was determined by exploiting the high reflectivity from HgTe and the low reflectivity from CdTe for the (002) Bragg reflection. Knowing the well and barrier widths we have been able to set an upper limit on the average Cd concentration of the barriers, \(\overline x_b\), by annealing several superlattices and then measuring the composition of the resulting alloy. \(\overline x_b\) was shown to decrease exponentially with decreasing barrier width. The structure of a very short period superlattice, i.e., 31.4 {\AA}, was also investigated by transmission electron microscopy, corroborating the x-ray diffraction results.},
  language  = {en}
}
@article{QiuHeLietal.1993,
  author    = {Qiu, Yueming and He, Li and Li, Jie and Yuan, Shixin and Becker, Charles R. and Landwehr, G.},
  title     = {Infrared photoconductor fabricated with HgTe/CdTe superlattice grown by molecular beam epitaxy},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37772},
  year      = {1993},
  abstract  = {An infrared photoconductor fabricated with a HgTe/CdTe superlattice grown on a GaAs substrate by molecular beam epitaxy is described here for the first time. The growth procedure, device fabrication, and measurement results are described. The results show that the device has relatively high uniformity and 1000 K black-body detectivity 2.4 X 10\(^9\) cm Hz\(^{1/2}\) W\(^{-1}\) . The photoconductivity decay method was used for determining carrier lifetime of the HgTe/CdTe superlattice, the measured lifetime is 12\(\mu\)s at 77 K, which is the longest lifetime ever reported for HgTe/CdTe superlattices and we believe that the increase of lifetime is mainly due to the reduction of dimensions.},
  language  = {en}
}
@article{GreinerPolignoneBeckeretal.1992,
  author    = {Greiner, P. and Polignone, L. and Becker, Charles R. and Geick, R.},
  title     = {Contactless measurement of the conductivity of II-VI epitaxial layers by means of the partially filled waveguide method},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37838},
  year      = {1992},
  abstract  = {We report the contactless determination of the conductivity, the mobility and the carrier concentration of II-VI semiconductors by means of the technique of the partially filled waveguide at a microwave frequency of 9 GHz. The samples are CdHgTe epitaxial layers, grown on CdZnTe substrates by molecular beam epitaxy. The conductivity is determined from the transmission coefficient of the sample in the partially filled waveguide. For the analysis of the experimental data, the complex transmission coefficient is calculated by a rigorous multi-mode matching procedure. By varying the conductivity of the sample, we obtain an optimum fit of the calculated data to the experimental results. Comparison with conductivity data determined by the van der Pauw method shows that our method allows to measure the conductivity with good accuracy. The behaviour of the transmission coefficient of the sample is discussed in dependence on the layer conductivity, the layer thickness and the dielectric constant of the substrate. The calculations require to consider in detail the distribution of the electromagnetic fields in the sample region. The usual assumption of a hardly disturbed TE\(_{10}\) mode cannot be used in our case. By applying a magnetic field in extraordinary Voigt configuration. galvanomagnetic measurements have been carried out which yield the mobility and thus the carrier concentration. These results are also in good agreement with van der Pauw transport measurements.},
  language  = {en}
}
@article{ShanjiaXinzhangGreineretal.1992,
  author    = {Shanjia, Xu and Xinzhang, Wu and Greiner, P. and Becker, Charles R. and Geick, R.},
  title     = {Microwave transmission and reflection of stratified lossy dielectric segments partially filled waveguide},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37958},
  year      = {1992},
  abstract  = {The microwave transmission and reßection is evaluated for stratified lossy dielectric segments partially filling the rectangular waveguide by the method which combines the multimode network theory with the rigorous mode matching procedure. As an example, we investigate in detail the microwave scattering properties of II-VI-epitaxial layer on a lossy dielectric substrate inserted in the rectangular waveguide. The experimental data verify the accuracy and the effectiveness of the present method. Extensive numerical results are presented to establish useful guidelines for the contactless microwave measurement of the conductivity of the epitaxiallayer.},
  language  = {en}
}
@article{WuBeckerWaagetal.1992,
  author    = {Wu, Y. S. and Becker, Charles R. and Waag, A. and Bicknell-Tassius, R. N. and Landwehr, G.},
  title     = {Thermal effects on (100) CdZnTe substrates as studied by x-ray photoelectron spectroscopy and reflection high energy electron diffraction},
  issn      = {0003-6951},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37801},
  year      = {1992},
  abstract  = {The influence of different CdZnTe substrate treatments prior to II-VI molecular beam epitaxial growth on surface stoichiometry, oxygen, and carbon contamination has been studied using x-ray photoelectron spectroscopy and reflection high energy electron diffraction. Heating the substrate at 300 °C can eliminate oxygen contamination, but cannot completely remove carbon from the surface. Heating at higher temperatures decreases the carbon contamination only slightly, while increasing the Zn-Cd ratio on the surface considerably. The magnitude of the latter effect is surprising and is crucial when one is using lattice matched CdZnTe (Zn 4\%) substrates.},
  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}
}
@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{SchubertKrausKenkliesetal.1992,
  author    = {Schubert, D.W. and Kraus, M.M and Kenklies, R. and Becker, Charles R. and Bicknell-Tassius, R.N.},
  title     = {Composition and wavelength dependence of the refractive index in Cd\(_{1-x}\)Mn\(_x\)Te epitaxial layers},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37716},
  year      = {1992},
  abstract  = {We have investigated Cd\(_{1-x}\)Mn\(_x\)Te thin films with Mn concentrations of x=0.12, 0.18, 0.30, 0.52, and 0.70. These single crystal layers were grown by molecular beam epitaxy on [001] CdTe substrates. The real part of the refractive index, n, was determined below the band-gap Eo in the range of 0.5-2.5 eV at T=300 K. The parallel reOectivity was measured near the Brewster angle at the YAG laser wavelength of 1.064 J.Lm (hv= 1.165 eV). Combining these results with the optical pathlength results (nd) of reOection measurements in a Fourier spectrometer we have determined n(x,v) over a wide spectral range by utilizing a three parameter fit. The accuracy of these results for n should improve waveguide designs based on this material.},
  language  = {en}
}
@article{BeckerWuWaagetal.1991,
  author    = {Becker, Charles R. and Wu, Y. S. and Waag, A. and Kraus, M. M. and Landwehr, G.},
  title     = {The orientation independence of the CdTe-HgTe valence band offset as determined by x-ray photoelectron spectroscopy},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-30784},
  year      = {1991},
  abstract  = {No abstract available},
  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}
}
@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{TackeSchuberthBeckeretal.1982,
  author    = {Tacke, M. and Schuberth, W. and Becker, Charles R. and Haas, L. D.},
  title     = {The dielectric constant of PbTe at 4.2 K and \(\tilde ν\)=84.15 cm\(^{-1}\), 96.97 cm\(^{-1}\), 103.60 cm\(^{-1}\)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-30821},
  year      = {1982},
  abstract  = {The dielectric constant of a PbTe epitaxial layer has been measured by surface wave spectroscopy using an optically pumped far-infrared laser and the technique of attenuated total reflection.},
  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{KlitzingBecker1976,
  author    = {Klitzing, K. von and Becker, Charles R.},
  title     = {Far infrared photoconductivity of residual acceptors in pure tellurium},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-31278},
  year      = {1976},
  abstract  = {The photoconductivity of both undeformed and deformed Te samples has been investigated at liquid He temperature by means of a Fourier spectrometer. Three peaks were usually found in the spectra of undeformed samples at 11, 24 and 46 cm\(^{-1}\). These are shown to be due to three different chemical impurities. The deformed samples are characterized by additional structure at higher frequencies.},
  language  = {en}
}
@misc{KoehlerBecker1976,
  author    = {K{\"o}hler, H. and Becker, Charles R.},
  title     = {Infrared-active lattice vibrations in SnSe\(_2\)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-30838},
  year      = {1976},
  abstract  = {No abstract available},
  language  = {en}
}
@article{BeckerLauGEICKetal.1975,
  author    = {Becker, Charles R. and Lau, Ph. and GEICK, R. and Wagner, V.},
  title     = {Antiferromagnetic Resonance in NiO:Co\(^{2+}\) and NiO:Fe\(^{2+}\)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-30772},
  year      = {1975},
  abstract  = {No abstract available.},
  language  = {en}
}
@article{KoehlerBecker1974,
  author    = {K{\"o}hler, H. and Becker, Charles R.},
  title     = {Optically active lattice vibrations in Bi\(_2\)Se\(_3\)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-31296},
  year      = {1974},
  abstract  = {The preparation of Bi2Sea single crystals with low free carrier densities allowed an investigation of the lattice vibrations to be carried out from the reflectivity of cleavage planes at nearly normal incidence of the radiation (E ~ c). The experimental results ean be explained with two classical oscillators, whose eigenfrequencies oceur at 92 and 69.5 cm-I. The static dielectric constant was determined to be 100 ± 10 for E ~ c.},
  language  = {en}
}
@misc{DeciusBeckerFredericks1973,
  author    = {Decius, J. C. and Becker, Charles R. and Fredericks, W. J.},
  title     = {Erratum: Force constants of the metaborate ion in alkali halides},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37992},
  year      = {1973},
  abstract  = {Erratum for the article: Decius, J. C. ; Becker, Charles R. ; Fredericks, W. J. : Force constants of the metaborate ion in alkali halides, In: THE JOURNAL OF CHEMICAL PHYSICS (1972), 56, 10, 5189-5190.},
  language  = {en}
}
@misc{UnkelbachBeckerKoehleretal.1973,
  author    = {Unkelbach, K. H. and Becker, Charles R. and K{\"o}hler, H. and Middendorff, A. V.},
  title     = {Optical Phonons of Bi\(_2\)Te\(_3\)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-30809},
  year      = {1973},
  abstract  = {No abstract available},
  language  = {en}
}
@article{DeciusBeckerFredericks1972,
  author    = {Decius, J. C. and Becker, Charles R. and Fredericks, W. J.},
  title     = {Force constants of the metaborate ion in alkali halides},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-50935},
  year      = {1972},
  abstract  = {No abstract available},
  subject      = {Physik},
  language  = {en}
}
@article{BeckerMartin1972,
  author    = {Becker, Charles R. and Martin, T. P.},
  title     = {Infrared absorption by Impurity-pair resonant modes in NaCl:F},
  isbn      = {1098-0121},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37840},
  year      = {1972},
  abstract  = {New resonant-mode infrared absorption lines have been observed in NaCl with high concentrations of fluorine impurities. The quadratic concentration dependence of the strength of these lines indicates that they are due to pairs of fluorine impurities. At the resonant frequencies, the motion of some host ions appears to be as important as the motion of the impurities themselves.},
  subject      = {Festk{\"o}rperphysik},
  language  = {en}
}
@misc{IshigamaBeckerMartinetal.1972,
  author    = {Ishigama, M. and Becker, Charles R. and Martin, T. P. and Prettl, W.},
  title     = {Impurity-pair mode in NaCl:KF},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-31255},
  year      = {1972},
  abstract  = {No abstract available},
  language  = {en}
}
@article{Becker1971,
  author    = {Becker, Charles R.},
  title     = {Evidence for a quasi-phonon gap in CsCl},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-30767},
  year      = {1971},
  abstract  = {The observed impurity induced far-infrared absorption in CsCl : Rb\(^+\) and CsCl : K\(^+\) is compared with a calculated density of acoustic phonon states in CsCl. The absorption due to CsCl : Rb\(^+\) displays a minimum between the acoustic and optic phonon bands. A narrow line is observed in CsCl: K\(^+\) at 85.8 cm\(^{-1}\) which falls in this quasi-phonon gap.},
  language  = {en}
}
@article{BeckerNath1970,
  author    = {Becker, Charles R. and Nath, G.},
  title     = {Optical properties of LiIO\(_3\) in the far infrared},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37905},
  year      = {1970},
  abstract  = {No abstract available},
  language  = {en}
}
@article{Becker1970,
  author    = {Becker, Charles R.},
  title     = {Impurity-induced absorption in or near the phonon gap of KI},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-30757},
  year      = {1970},
  abstract  = {In or near the phonon gap of KI a single weak line due to OW (OD\(^-\)) at 69.7 (69.3) cm\(^{-1}\) has been observed. A second and much stronger line at 94.1 cm\(^{-1}\) was shown not to be related to OH\(^-\), but instead is thought to be due to CO\(_3\).},
  language  = {en}
}