| 초록 |
The stochiometric mix of evaporating materials for the CuGaSe2 single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, CuGaSe2 mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperature were 610 ℃ and 450 ℃, respectively. The crystalline structure of single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). From the photocurrent spectrum by illumination of perpendicular light on the c-axis of the CuGaSe2 single crystal thin film, we have found that the values of spin orbit splitting ΔSo and the crystal field splitting ΔCr were 91 meV and 249.8 meV at 20 K, respectively. From the photoluminescence measurement on CuGaSe2 single crystal thin film, we observed free excition (EX) existing only high quality crystal and neutral bound exiciton (Do,X) having very strong peak intensity. Then, the full-width-at -half-maximum(FWHM) and binding energy of neutral acceptor bound excition were 8 meV and 35.2 meV, respectivity. By Haynes rule, an activation energy of impurity was 355.2 meV. |
