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利用脉冲激光沉积(PLD)法,在蓝宝石(0001)平衬底上成功制备了c轴一致取向的Ca3Co4O9薄膜。利用X射线衍射(XRD)分析测定了薄膜的相结构和生长取向。研究了不同衬底温度与不同原位氧压对Ca3Co4O9薄膜结晶质量与生长取向的影响,确定了最佳生长条件。利用这一条件在倾斜Al2O3(0001)衬底上制备了Ca3Co4O9薄膜。研究发现,当Ca3Co4O9薄膜被波长248nm,脉冲宽度20ns的脉冲激光照射时,在薄膜两端存在较大的激光感生热电电压(LITV)信号,峰值电压达到4.4V,其上升沿为36ns,半峰全宽(FWHM)为131ns。可以认为这种激光感生热电电压信号是由于Ca3Co4O9薄膜面内与面间泽贝克(Seebeck)系数张量的各向异性引起的。
The c-axis uniformly oriented Ca3Co4O9 thin films were successfully deposited on sapphire (0001) flat substrates by pulsed laser deposition (PLD). The phase structure and growth orientation of the films were characterized by X-ray diffraction (XRD). The effects of different substrate temperatures and different in-situ oxygen pressures on the crystal quality and growth orientation of Ca3Co4O9 thin films were studied, and the optimum growth conditions were determined. Using this condition, a Ca3Co4O9 thin film was prepared on an inclined Al2O3 (0001) substrate. The results show that when the Ca3Co4O9 thin film is irradiated by a pulsed laser with a wavelength of 248 nm and a pulse duration of 20 ns, there is a large laser induced thermoelectric voltage (LITV) signal at the two ends of the thin film with a peak voltage of 4.4V and a rising edge of 36ns, The peak full width (FWHM) is 131 ns. It is believed that this laser-induced thermoelectric voltage signal is due to the anisotropy of the Seebeck coefficient tensor in-plane and inter-plane of the Ca3Co4O9 film.