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测量了在不同氧压下退火生长的YBa2Cu3O7-x(YBCO)薄膜中的激光感生热电电压(LITV)信号,发现随退火氧压的增大可使LITV信号的峰值有2—4倍的增强,并且变化趋势与薄膜热电势的各向异性随氧含量的变化规律相同.波长在473—808nm范围内的连续激光辐照,在5000Pa的氧压下退火生长的YBCO薄膜中探测到的LITV信号最大;而紫外脉冲激光辐照时,LITV信号的最大值出现在退火氧压为105Pa的薄膜中.LITV信号的光响应时间随退火氧压的增大而减小,理论分析表明,这一结果是由于退火氧压的提高导致薄膜材料的热扩散系数增大所致.在退火氧压为5000Pa的YBCO薄膜中探测到响应最快的LITV信号,对紫外脉冲激光的响应时间为78ns,并且信号的上升时间只有29ns,与激光的脉冲宽度(约为28ns)相当.
The laser-induced thermoelectric voltage (LITV) signals in YBa2Cu3O7-x (YBCO) thin films annealed at different oxygen pressures were measured and found to increase 2-4 times the peak LITV signal with increasing annealing oxygen pressure , And the change trend and the thermoelectric anisotropy of the film with the same change of oxygen content.LEDV signal detected in continuous YBCO film annealed at oxygen pressure of 5000Pa under continuous laser irradiation with a wavelength of 473-808nm The maximum value of LITV signal appears in the film with an annealing oxygen pressure of 105Pa.The photoresponse time of LITV signal decreases with the increase of annealing oxygen pressure.The theoretical analysis shows that this result Is due to the increase of the annealing oxygen pressure resulting in the increase of the thermal diffusivity of the thin film material.The fastest response LITV signal was detected in the YBCO film annealed at oxygen pressure of 5000Pa and the response time to ultraviolet pulsed laser was 78ns and the signal The rise time of only 29ns, and the laser pulse width (about 28ns) is equivalent.