| 초록 |
A stoichiometric mixture of evaporating materials for ZnGa2Se4 single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, ZnGa2Se4 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 ℃ and 450 ℃, 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 ZnGa2Se4 single crystal thin films measured from Hall effect by van der Pauw method are 9.63×1017 cm-3 and 296 cm2/V․s at 293 K, respectively. From the photocurrent spectrum by illumination of perpendicular light on the c-axis of the ZnGa2Se4 single crystal thin film, we have found that the values of spin orbit splitting Δso and the crystal field splitting Δcr were 251.9 meV and 183.2 meV at 10 K, respectively. From the photoluminescence measurement on the ZnGa2Se4 single crystal thin film, we observed free excition (EX) existing only high quality crystal and neutral bound exiciton (A0,X) having very strong peak intensity. Then, the full-width-at -half-maximum(FWHM) and binding energy of neutral acceptor bound excition were 11 meV and 24.4 meV, respectivity. By Haynes rule, an activation energy of impurity was 122 meV. |
