arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2007.15561physics.opticscond-mat.mes-hall
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合金化控制Au-Ag薄膜的热载流子弛豫时间

Control of hot-carrier relaxation time in Au-Ag thin films through alloying

Sarvenaz Memarzadeh, Kevin J. Palm, Thomas E. Murphy, Marina S. Leite, Jeremy N. Munday

摘要:

结构的等离子体共振主要由其光学性质和几何形状决定,可以对其进行修改以使热载流子光电探测器具有优异的性能。最近,金属合金在通过化学成分工程调谐等离子体结构的共振方面发挥了突出的作用。然而,目前还不清楚如何合金化修改所产生的热载流子的时间动态。在这项工作中,我们阐明的作用,化学成分上的弛豫时间的热载流子的原型辅助Ag 1-x薄膜系统。通过在可见光波长范围内的时间分辨光谱测量,我们测量了成分依赖的弛豫时间,其变化高达8倍,以获得恒定的泵浦流率。令人惊讶的是,我们发现,除了2%的银到金膜可以增加热载流子寿命约35%,在固定的注量下,作为一个结果,在光学损耗的减少。此外,弛豫时间被发现是成反比的介电常数的虚部。我们的研究结果表明,合金化是一种很有前途的方法,以有效地控制热载流子弛豫时间的金属。

英文摘要:

The plasmon resonance of a structure is primarily dictated by its optical properties and geometry, which can be modified to enable hot-carrier photodetectors with superior performance. Recently, metal-alloys have played a prominent role in tuning the resonance of plasmonic structures through chemical composition engineering. However, it has been unclear how alloying modifies the time dynamics of generated hot-carriers. In this work, we elucidate the role of chemical composition on the relaxation time of hot-carriers for the archetypal Aux Ag1-x thin-film system. Through time-resolved optical spectroscopy measurements in the visible wavelength range, we measure composition-dependent relaxation times that vary up to 8x for constant pump fluency. Surprisingly, we find that the addition of 2% of Ag into Au films can increase the hot carrier lifetime by approximately 35% under fixed fluence, as a result of a decrease in optical loss. Further, the relaxation time is found to be inversely proportional to the imaginary part of the permittivity. Our results indicate that alloying is a promising approach to effectively control hot-carrier relaxation time in metals.

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