[Title] The Effect of Fermi Level Motion on the Optical, ESR and Transport Properties of CuInSe_{2}
[Authors] Katsuaki Sato, Nobuyuki Nishikawa{*a}, Igor Aksenov{*b} , Takeshi Shinzato and Hisayuki Nakanishi^{1}
[Affiliations] Faculty of Technology, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184, Japan
^{1} Faculty of Science and Technology, Science University of Tokyo, Noda, Chiba 278, Japan}
{*a} Present address: Fujitsu Corporation Ltd., Kamikotanaka, Nakaharaku, Kawasaki, Kanagawa 211, Japan
{*b} Present address: Electrotechnical Laboratory, Umezono, Tsukuba, Ibaraki 305, Japan
[Journal]Jpn. J. Appl. Phys. 35 Part 1, No. 4A (1996) 2061-2067
[Keyword]CuInSe_{2}, inter-valence-band absorption, free-carrier absorption, Fe impurity, ESR, Fermi level
[Abstracts]The infrared (IR) absorption and ESR spectra of the CuInSe_{2} crystals,
grown by the normal freezing technique and subsequently annealed in various atmospheres,
have been studied in connection with the annealing-induced motion of the Fermi level relative to
the energy band edges. The degenerate n-type crystals exhibited a free-electron absorption,
while the p-type crystals showed both an inter-valence-band and a free-hole absorption,
from the analysis of which the energy positions of the Fermi level have been evaluated,
and the electrical parameters of the respective crystals have been estimated,
which have been compared with the experimental results. In the ESR spectra the signals
from iron residual impurity in its both divalent and trivalent charged states, as well as
the signals arising from native defects V_{Cu} and In_{Cu}, have been detected,
the intensities of the ESR signals being dependent on the composition of the samples and
the Fermi level position.
[Title] Magneto-optical Spectra in Fe(xML)/Au(xML) Artificially Ordered Superlattices
[Authors] K. Sato, T. Kondoa), J. Abe, H. Ikekame, M. Sano^{1}, S. Mitani^{1}, K. Takanashi^{1} and H. Fujimori^{1}
[Affiliations] Faculty of Technology, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184, Japan
^{1}Institute for Materials Research, Tohoku University, Katahira, Aoba-ku, Sendai, Miyagi 980-77, Japan
[Journal] J. Magn. Soc. Jpn. 20, No. 2 (1996) 197-200.
[Keyword] artificial superlattice, Fe(x mololayers) /Au (x monolayers) (x = 1,...,5), ordered structure, magneto-optical effect, energy band structure
[Abstracts] The spectra of the magneto-optical Kerr effect and optical constants were measured
in artificially ordered superlattices consisting of 1 to 5 monoatomic layers of Fe and Au.
The Kerr rotation spectra showed a prominent structure around 4 eV, which undergoes a shift
with layer thickness, the spectral features being quite different from those calculated
by the virtual optical constant method, which assumes that the superlattice is composed of
pure metallic layers. This result suggests the formation of a new ordered alloy with a period
extending up to 5 mololayers, which do not exist in the binary phase diagram of thermal
equilibrium. The magneto-optical structure around 4 eV is attributed to the Au 5d =>Fe 3d transition,
on the bases of results of the energy band calculation.
[Title] Hot-Wall Growth and Magneto-Optical Studies of MnSb Films on GaAs Substrates
[Authors] Hiroshi Ikekame, Yoshitaka Morishita and Katsuaki Sato
[Affiliations] Faculty of Technology, Tokyo Univ. of Agriculture and technology, Koganei, Tokyo 184, Japan
[Journal] J. Magn. Soc. Jpn. 20, No. 2 (1996) 181-184.
[Keyword] MnSb, GaAs, epitaxy, hot wall epitaxy, magneto-optical Kerr effect, hybrid magnetic semiconductor
[Abstracts]Ferromagnetic MnSb thin films were grown on GaAs (100) substrates by hot-wall epitaxy
(HWE) technique using polycrystalline powders of MnSb as an evaporation source.
the source and substrate temperatures were 650-700 {degree}C and 300-500 {degree}C,
respectively. The (10.1) oriented MnSb films of nearly stoichiometric composition
were grown on (100) GaAs. The polar magneto-optical Kerr rotation and elipticity spectra
were measured in the films, and showed almost the same spectra shape as that reported
previously in bulk single crystals, except that the magneto-optical effect of the films
was larger in the high-energy region than that of the single crystals.
[Title] Growth of CuInSe_{2} Thin Films by Triple-Ionized Beam Technique
[Authors] Hiroyuki Sano^{1}, Kenichi Kondo^{1} and Katsuaki Sato^{2}
[Affiliations] {1}Stanley Electric Co. Ltd., Yokohama, Kanagawa 225, Japan
{2} Tokyo Univ. of Agriculture and Technology, Koganei, Tokyo 184, Japan
[Journal] J. Cryst. Res. Technol. 31 (1996) Special Issue 349-352.
[Keyword] ionized beam technology, CuInSe_{2}, polycrystalline thin film, solar cells
[Abstracts] CuInSe_{2} thin films were prepared on the soda-lime glass substrate by the
triple-ionized beam deposition technique (IBT), in which Cu, In and Se vapors were ionized and
accelerated. the substrate temperature was as low as 300 {degree}C. The films were characterized
by X-ray diffraction, SEM, EPMA and ICP. As a result, we were able to obtain films with
improved grain size and the crystallinity by ionization of Se-vapor. Those films showed
a nearly stoichiometric composition with apparent grain size of more than 2 {mu}m.
Thus IBT turned out to be an appropriate technology for low temperature deposition of
high quality CuInSe_{2} thin films.
[Title] Photoluminescence Spectra in Single Crystals of CuAlS2 Doped with Rare-Earth Elements
[Authors]K. Sato, Y. Kimura, K. Shimizu, T. Ohgoh and Y. Kudo
[Affiliations] Tokyo University of Agriculture & Technology, Koganei, Tokyo 184, Japan
[Journal] J. Cryst. Res. Technol. 31 (1996) Special Issue, 713-716.
[Keyword] photoluminescence, rare-earth ions, single crystals of CuAlS_{2}, f-f transitions
[Abstracts]Photoluminescence studies in single crystals of CuAlS_{2} doped with a series of
rare-earth elements have been studied. Heavy rare earth ions were successfuly incorporated
showing PL spectra characteristic of f-f transitions of trivalent RE ions.
[Title] Optical and ESR Characterization of Iron Impurity in Cu-III-VI_{2} Semiconductors
[Authors]K. Sato, I. Aksenov{*1}, N. Nishikawa{*2}, T. Shinzato and H. Nakanishi^{1}
[Affiliations] Faculty of Technology, Tokyo University of Agriculture & Technology,
Koganei, Tokyo 184, Japan
^{1}Science University of Tokyo, Noda, Chiba 278, Japan
{*1} Present address: Electrotechnical Laboratories, Tsukuba, 305, Japan
{*2} Present address: Fujitsu Laboratories Ltd., Kamikotanaka, Kawasaki 211, Japan
[Journal] J. Cryst. Res. Technol. 31 (1996) Special Issue, 593-596.
[Keyword] Cu-III-VI_{2} semiconductors, Fe impurity, optical absorption, ESR spectrum
[Abstracts] Results of characterization of iron impurity in I-III-VI_{2} chalcopyrite type
crystals by means of infrared optical absorption and ESR spectroscopies are described.
[Title] Crystal Growth and Polarized Photoluminescence Spectra in Ce-doped Single Crystal of SrGa_2S_4
[Authors] Katsu TANAKA{1,2}, Tsuyoshi OHGOH{1},{*a}, Kazuya KIMURA{1}, Hajime YAMAMOTO{3},,Kiminari SHINAGAWA{4} and Katsuaki SATO{1}
[Affiliation] {1}Faculty of Technology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184
{2} NHK Science and Technical Research Laboratories, 1-10-11 Kinuta, Setagaya-ku, Tokyo 157
{3}Tokyo Engineering University, 1401-1 Katakura, Hachioji, Tokyo 192
{4}Faculty of Science, Toho University, Funabashi, Chiba 274
{*a}Present address: Fuji Photo Film Co. Ltd., Kaisei-machi, Kanagawa 258, Japan
[Journal] Jpn. J. Appl. Phys. 34 Pat 2, No. 12B (1995) L1651-L1654
[Keywords] SrGa_2S_4 thiogallate, Ce rare-earth ions, single crystals, polarized photoluminescence, crystal-field theory, electroluminescent display, chromaticity
[Abstracts]: Polarized photoluminescent (PL) spectra were measured in single crystals of
SrGa_{2}S_{4}:Ce prepared by chemical vapor transport technique. A PL band with double peaks
at 450 and 493 nm showed strong polarization dependence in shapes and intensities between
E {parallel to}c and E {perpendicular to} c polarizations. The PL spectra have been discussed
in the framework of the crystal-field theory by which the two peaks has been assigned to
transitions between crystal-field and L-S coupling multiplets of 5d- and 4f-states of
Ce^{3+} in D_{4h} symmetry.ˇˇCalculated polarized PL spectra based on the crystal-field
theory were in good agreement with the experimental ones. From these results we suggest
a possibility of controlling the chromaticity in blue EL phosphors using epitaxial films
with well-defined growth orientation.
[Title] MAGNETOOPTICAL SPECTRA OF MnSb CRYSTAL BETWEEN 1.2 AND 6.4 eV [Authors]Katsuaki Sato, Yasuhiro Tosaka and Hiroshi Ikekame [Affiliation]Faculty of Technology, Tokyo Univ. of Agriculture and Technology, Koganei, Tokyo 184, Japan [Journal] J. Magn. Soc. Jpn. 19, Suppl. S1 (1995) 255-258. [Keywords]Magnetooptical spectra, MnSb, Pt-doped MnSb, Bridgmann technique, bulk crystals [Abstracts]Magnetooptical spectra have been studied for photon energies between 1.2 and 6.4 eV in bulk crystals of undoped and Pt-doped MnSb. Kerr rotation of undoped crystals showed a prominent zero-crossing behavior around 4.5 eV. The zero-crossing energy moved to 4.1 eV in Pt-doped samples, which were explained by the averaged spectra of separated two phases of MnSb and PtMnSb.
[Title] Growth of MnSb Thin Films on CdTe Substratesby Hot-Wall Epitaxy
[Authors]Jaime Gordon*1, Hiroshi Ikekame, Tomohiro Nakamura, Jun-ichi Itabashi, Hiroshi Nagayoshi and Katsuaki Sato*2
[Affiliation]Faculty of Technology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184
*1 Visiting fellow of the Japan Society for the Promotion of Science.
Present address: El-Sol Technologies Ltd., P.O.B. 2699, Natanya 42170, Israel.
*2To whom reprint requests should be addressed.
[Journal]Jpn. J. Appl. Phys. 36, [5B] L607-L610.
[Keywords]CdTe, MnSb, epitaxial film, hot wall epitaxy, polar magnetooptical Kerr spectrum
[Abstracts]Ferromagnetic MnSb thin films were grown on CdTe (110) substrates for the first time by hot-wall epitaxy (HWE) technique using polycrystalline powders of MnSb as an evaporation source. The crystal orientation of these thin films was determined by X-ray diffractometry (XRD). The chemical composition of the films was determined by means of electron-probe microanalysis (EPMA) and by electron spectroscopy for chemical analysis (ESCA) depth profiling. Polar magnetooptical Kerr rotation spectra were measured in the 1.2 eV to 4 eV photon energy range.
[Title] Magnetooptical Properties of MnSb Grown by Atomic-hydrogen Assisted Hot-Wall Epitaxy
[Authors]H. Ikekame*, M. Akita, T. Nakamura, J. Itabashi, and K. Sato
[Affiliation]Faculty of Technology, Tokyo University of Agriculture and Technology, Koganei 184
[Journal]J. Magn. Soc. Jpn. 21 [4-2] (1997) 349-352.
[Keywords]MnSb, GaAs, ferromagnet/semiconductor hybrid structure, hot-wall epitaxy, atomic-hydrogen, AFM, morphology, flatness, polar magnetooptical Kerr effect
[Abstracts]MnSb films were prepared on GaAs(100) and (111)B substrates by atomic-hydrogen assisted hot-wall epitaxy technique. Atomic-force microscopy observation revealed a drastic improvement in the surface flatness of MnSb films grown with irradiation of atomic-hydrogen. It was found from the X-ray diffraction that growth surface of MnSb films was in those grown on GaAs(100) substrates, while it was (0001) on GaAs(111)B. Spectra of the optical reflectivity and the polar magnetooptical Kerr effect were measured in the films obtained and analyzed in terms of electric conductivity tensor.
[Title]Magneto-optical Spectra of MnAs on GaAs Grown by HWE
[Authors]M.Akita, H.Ikekame*, T.Nakamura, J.Itabashi and K.Sato
[Affiliation]Faculty of Technology, Tokyo University of Agriculture and Technology, Koganei 184
[Journal]J. Magn. Soc. Jpn., 21 [4-2] (1997) 353-355.
[Keywords]MnAs, GaAs, atomic-hydrogen, hot-wall epitaxy, polar magneto-optical Kerr rotation, polar magneto-optical Kerr ellipticity, dielectric permeability
[Abstracts]Ferromagnetic MnAs thin films were grown on GaAs (100) and (111)B substrates by the atomic-hydrogen-assisted hot-wall epitaxy technique, using polycrystalline powder of MnAs as evaporation source. The source and substrate temperatures were 700oC and 800oC, respectively. The surface orientation of the MnAs films grown on (100) GaAs substrates were (101bar1) and (101bar2), those on (111)B GaAs was (0001). The polar magneto-optical Kerr rotation and ellipticity spectra and reflectivity spectra were measured in the films. The dielectric permeability spectra were calculated from experimental data, from which the magneto-optical spectra were analyzed.
[Title]Effects of atomic-hydrogen assistance in hot-wall epitaxy growth of MnSb/GaAs heterostructures
[Authors]H. Ikekamea*, Y. Yanase, T. Ishibashi, Y. Morishita, T. Saito and K. Sato
[Affiliation]Faculty of Technology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184, Japan
* present address Hitachi Central Labs., Tokyo 185, Japan
[Journal]J. Cryst. Growth 173 (1997) 218-221.
[Keywords]MnSb; GaAs; ferromagnet/semiconductor hybrid structure; hot-wall epitaxy; atomic hydrogen
[Abstracts]Prominent improvement of surface flatness was observed in MnSb films prepared by atomic-hydrogen (H*) assisted HWE (hot wall epitaxy) technique on GaAs substrate. The effect is discussed in terms of surfactant effect of atomic hydrogen.
Click to see Fig.1 AFM image of MnSb grown on GaAs(100) without assistance of atomic H,
and Fig.2AFM image of MnSb grown on a GaAs (100) substrate with assistance of atomic H.
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