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A stoichiometric mixture of evaporating materials for ZnAl 2 Se 4 single-crystal thin films was prepared in a horizontal electric furnace. These ZnAl 2 Se 4 polycrystals had a defect chalcopyrite structure, and its lattice constants were a 0 = 5.5563 Å and c 0 = 10.8897 Å.To obtain a single-crystal thin film, mixed ZnAl 2 Se 4 crystal was deposited on the thoroughly etched semiinsulating GaAs(100) substrate by a hot wall epitaxy (HWE) system. The source and the substrate temperatures were 620 o C and 400 o C, respectively. The crystalline structure of the single-crystal thin film was investigated by using a double crystal Xray rocking curve and X-ray diffraction ω-2θ scans. The carrier density and mobility of the ZnAl 2 Se 4 single-crystal thin film were 8.23 × 10 16 cm −3 and 287 m 2 /vs at 293 K, respectively. To identify the band gap energy, the optical absorption spectra of the ZnAl 2 Se 4 single-crystal thin film was investigated in the temperature region of 10-293 K. The temperature dependence of the direct optical energy gap is well presented by Varshni's relation: E g (T) = E g (0) − (αT 2 /T + β). The constants of Varshni's equation had the values of E g (0) = 3.5269 eV, α = 2.03 × 10 −3 eV/K and β = 501.9 K for the ZnAl 2 Se 4 single-crystal thin film. The crystal field and the spin-orbit splitting energies for the valence band of the ZnAl 2 Se 4 were estimated to be 109.5 meV and 124.6 meV, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that splitting of the ∆so definitely exists in the Γ 5 states of the valence band of the ZnAl 2 Se 4 /GaAs epilayer. The three photocurrent peaks observed at 10 K are ascribed to the A 1 -, B 1 -exciton for n = 1 and C 21 -exciton peaks for n = 21.

The evaporating materials for MgGa 2 Se 4 single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, MgGa 2 Se 4 compounded polycrystal powder was deposited on thoroughly etched semi-insulated GaAs(100) substrate by the hot wall epitaxy (HWE) method system. The source and substrate temperatures of optimized growth conditions, were 610 Received: Oct. 31, 2013, Revised: Dec. 31, 2013, Accepted: Jan. 2, 2014 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License(http://creativecommons.org/ licenses/bync/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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