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本工作提出了脉冲激光沉积法生长Cu2Se热电材料薄膜中维持较高的激光切削能量密度对于实现薄膜与靶材成分等比例传输的重要性。使用较高的脉冲激光能量生长的Cu2Se薄膜具有纯的?-相,并具有与靶材相近的化学组分。这主要是因为较高的激光能量可以更加有效地引起等离子体对激光-固体直接作用的屏蔽,这可以使得靶材中的铜和硒元素的激光切削量更加接近靶材的化学计量比。由于硒具有较高的蒸汽压,降低激光能量会加强激光与固体的直接作用,从而更有效地切削硒元素,导致所沉积薄膜中产生铜缺陷。进一步讨论了所使用的氩气背景气体压力对于所生长的Cu2Se薄膜热电性能的影响。当使用高激光能量低背景气体压力时,所生长的薄膜具有最佳的热电性能。
In this work, the importance of maintaining high laser cutting energy density in Cu2Se thermoelectric thin films grown by pulsed laser deposition is put forward in order to realize the proportional transmission of film and target components. Cu2Se films grown with higher pulsed laser energy have a pure? -phase and have similar chemical composition to the target. This is mainly because the higher laser energy can more effectively cause the plasma to shield the laser-solid direct action, which can make the laser cutting amount of copper and selenium in the target closer to the target stoichiometry. Since selenium has a high vapor pressure, reducing the laser energy will enhance the direct effect of the laser with the solid, cutting the selenium more efficiently and causing copper defects in the deposited film. The effects of the argon background gas pressure used on the thermoelectric properties of the grown Cu2Se thin films are further discussed. The grown films have the best thermoelectric properties when using high laser energy with low background gas pressure.