Hot Wall Epitaxy(HWE)법에 의한 BaAl2Se4 단결정 박막 성장과 광전도 특성
Growth and Optical Conductivity Properties for BaAl2Se4 Single Crystal Thin Film by Hot Wall Epitaxy
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A stoichiometric mixture of evaporating materials for BaAl2Se4 single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, BaAl2Se4 mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperatures were 610 oC and 410 oC, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of BaAl2Se4 single crystal thin films measured from Hall effect by van der Pauw method are 8.29×10-16 cm-3 and 278 cm2/vs at 293K, respectively. The temperature dependence of the energy band gap of the BaAl2Se4 obtained from the absorption spectra was well described by the Varshni's relation, Eg(T) = 3.4205 eV − (4.3112 × 10-4 eV/K)T2/(T + 232 K). The crystal field and the spin-orbit splitting energies for the valence band of the BaAl2Se4 have been estimated to be 249.4 meV and 263.4 meV, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the Δso definitely exists in the 5 states of the valence band of the BaAl2Se4/GaAs epilayer. The three photocurrent peaks observed at 10 K are ascribed to the A1-, B1-exciton for n=1 and C31-exciton peaks for n=31.
Abstract
A stoichiometric mixture of evaporating materials for BaAl2Se4 single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, BaAl2Se4 mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperatures were 610 oC and 410 oC, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of BaAl2Se4 single crystal thin films measured from Hall effect by van der Pauw method are 8.29×10-16 cm-3 and 278 cm2/vs at 293K, respectively. The temperature dependence of the energy band gap of the BaAl2Se4 obtained from the absorption spectra was well described by the Varshni's relation, Eg(T) = 3.4205 eV − (4.3112 × 10-4 eV/K)T2/(T + 232 K). The crystal field and the spin-orbit splitting energies for the valence band of the BaAl2Se4 have been estimated to be 249.4 meV and 263.4 meV, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the Δso definitely exists in the 5 states of the valence band of the BaAl2Se4/GaAs epilayer. The three photocurrent peaks observed at 10 K are ascribed to the A1-, B1-exciton for n=1 and C31-exciton peaks for n=31.
참고문헌 (17)
- Von WILFRIED KLEE, "Darstellung und Struktur von BaAl2Se4, BaGa2Se4, CaGa2Se4 und CaIn2Te4", Z. anorg. allg, 479, pp.125~133 (1981)
- Moon-Seog Jin, "Photoluminescence spectra of undoped and Sm3+-doped BaAl2S4 and BaAl2Se4 single crystals", J. Mater. Res, 16(5) (2001)
- Jae-Mo Goh, "Opitcal properties of undoped and Ho3+, Er3+, and Tm3+-doped BaAl2S4 and BaAl2Se4 single crystals", Journal of Applied Physics, 88(7) (2000)
- S. P. Yadav, "Photoelectrochemical properties of spray deposited n-ZnIn2Se4 thin film", Solar Energy Materials & Solar Cells, 92, pp.453~456 (2008)
- J. Filipowicz, "Influence of Y-Irradiation on the optical and electrical properties of BaAl2Se4 films", Radiat. Phys. Chem, 50(2), pp.175~177 (1999)
- A. A. Vaipolin, "Radiative recombination in BaAl2Se4", Semiconductors, 37, pp.432~ (2003)
- T. A. Hendia, "Optical absorption behavior of evaporated BaAl2Se4 thin films", Thin Solid Films, 261, pp.322~327 (1955)
- K. J. Hong, "Structural and optical of CuGaSe2 layers grown by hot wall epitaxy", J. Crystal Growth, 310, pp.2717~2723 (2008)
- B. D. Cullity, "Elements of X-ray diffractions" (1985), Addson-Wesley
- H. Fujita, "Electron radition damage in Cadium-Selenide crystal at liquid-helium temperrature", J. Phys. Soc., 20, pp.109~ (1965)
- Y. P. Varshni, "Far-infrared optical absorption of Fe2+ in ZnSe", Physica, 34, pp.149~ (1967)
- J. L. Shay, "Analysis of the electrical and luminescent properties of BaAl2Se4", Phys. Rev., 9(4), pp.1719~ (1974)
- J. Hopfield, "BaAl2Se4", CdS heterojunction photovoltaic detectors, 1960, pp.15, 97~
- J. L. Shay, "Ternary chalcopyrite semiconductor : Growth, electronic properties and applications" (1975), Pergamon Press
- J. L. Birman, "Luminescence and impurity states in BaAl2Se4", Phys. Rev. Lett, 2, pp.159~ (1959)
- M. L. Glasser, "Polycrystalline BaAl2Se4 photoelectrochemical cells", J. Phys. Chem. Solids, 10, pp.229~ (1959)
- K. Cho, "Excitons, Topics in Current Physics", pp.18~ (1979), Springer-Verlag