Tagliabue Giulia, DuChene Joseph S, Habib Adela, Sundararaman Ravishankar, Atwater Harry A
Thomas J. Watson Laboratory of Applied Physics and Joint Center for Artificial Photosynthesis, California Institute of Technology, Pasadena, California 91125 United States.
Laboratory of Nanoscience for Energy Technologies (LNET), EPFL, 1015 Lausanne, Switzerland.
ACS Nano. 2020 May 26;14(5):5788-5797. doi: 10.1021/acsnano.0c00713. Epub 2020 Apr 27.
Among all plasmonic metals, copper (Cu) has the greatest potential for realizing optoelectronic and photochemical hot-carrier devices, thanks to its CMOS compatibility and outstanding catalytic properties. Yet, relative to gold (Au) or silver (Ag), Cu has rarely been studied and the fundamental properties of its photoexcited hot carriers are not well understood. Here, we demonstrate that Cu nanoantennas on type gallium nitride (-GaN) enable hot-hole-driven photodetection across the visible spectrum. Importantly, we combine experimental measurements of the internal quantum efficiency (IQE) with theoretical modeling to clarify the competing roles of hot-carrier energy and mean-free path on the performance of hot-hole devices above and below the interband threshold of the metal. We also examine Cu-based plasmonic photodetectors on corresponding -type GaN substrates that operate via the collection of hot electrons. By comparing hot hole and hot electron photodetectors that employ the same metal/semiconductor interface (Cu/GaN), we further elucidate the relative advantages and limitations of these complementary plasmonic systems. In particular, we find that harnessing hot holes with -type semiconductors is a promising strategy for plasmon-driven photodetection across the visible and ultraviolet regimes. Given the technological relevance of Cu and the fundamental insights provided by our combined experimental and theoretical approach, we anticipate that our studies will have a broad impact on the design of hot-carrier optoelectronic devices and plasmon-driven photocatalytic systems.
在所有等离子体金属中，铜（Cu）因其与互补金属氧化物半导体（CMOS）的兼容性和出色的催化性能，在实现光电子和光化学热载流子器件方面具有最大潜力。然而，相对于金（Au）或银（Ag），铜很少被研究，其光激发热载流子的基本特性也尚未得到充分理解。在这里，我们证明了在氮化镓（-GaN）型衬底上的铜纳米天线能够实现跨可见光谱的热空穴驱动光探测。重要的是，我们将内部量子效率（IQE）的实验测量与理论建模相结合，以阐明热载流子能量和平均自由程在金属带间阈值上下的热空穴器件性能中的竞争作用。我们还研究了基于铜的等离子体光探测器，该探测器在相应的 - 型氮化镓衬底上通过热电子的收集来工作。通过比较采用相同金属/半导体界面（铜/氮化镓）的热空穴和热电子光探测器，我们进一步阐明了这些互补等离子体系统的相对优势和局限性。特别是，我们发现利用 - 型半导体中的热空穴是在可见光和紫外光范围内进行等离子体驱动光探测的一种有前途的策略。鉴于铜的技术相关性以及我们结合实验和理论方法所提供的基本见解，我们预计我们的研究将对热载流子光电器件和等离子体驱动光催化系统的设计产生广泛影响。
