@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{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{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} } @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{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} } @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{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{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{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} }