| 초록 |
ZnO epilayer were synthesized by the pulesd laser deposition(PLD) process on Al2O3 substrate after irradiating the surface of the ZnO sintered pellet by the ArF(193nm) excimer laser. The substrate temperatures was 400℃. The crystalline structure of epilayer was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of ZnO epilayer measured with Hall effect by van der Pauw method are 8.27×1016 cm-3 and 299 cm2/V․s at 293K, respectively. The temperature dependence of the energy band gap of the ZnO obtained from the absorption spectra was well described by the Varshni's relation, Eg(T) = 3.3973 eV - (2.69 × 10-4 eV/K)T2/(T + 463K).The crystal field and the spin-orbit splitting energies for the valence band of the ZnO have been estimated to be 0.0087 eV and 0.2329 eV at 10K, 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 Γ6 states of the valence band of the ZnO. The three photocurrent peaks observed at 10K are ascribed to the A1-, B1-, and C1-exciton peaks for n = 1. |
