Otto Lauren M, Gaulding E Ashley, Chen Christopher T, Kuykendall Tevye R, Hammack Aeron T, Toma Francesca M, Ogletree D Frank, Aloni Shaul, Stadler Bethanie J H, Schwartzberg Adam M
Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, USA.
The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, USA.
Sci Rep. 2021 Apr 7;11(1):7656. doi: 10.1038/s41598-021-86813-y.
Surface plasmons have found a wide range of applications in plasmonic and nanophotonic devices. The combination of plasmonics with three-dimensional photonic crystals has enormous potential for the efficient localization of light in high surface area photoelectrodes. However, the metals traditionally used for plasmonics are difficult to form into three-dimensional periodic structures and have limited optical penetration depth at operational frequencies, which limits their use in nanofabricated photonic crystal devices. The recent decade has seen an expansion of the plasmonic material portfolio into conducting ceramics, driven by their potential for improved stability, and their conformal growth via atomic layer deposition has been established. In this work, we have created three-dimensional photonic crystals with an ultrathin plasmonic titanium nitride coating that preserves photonic activity. Plasmonic titanium nitride enhances optical fields within the photonic electrode while maintaining sufficient light penetration. Additionally, we show that post-growth annealing can tune the plasmonic resonance of titanium nitride to overlap with the photonic resonance, potentially enabling coupled-phenomena applications for these three-dimensional nanophotonic systems. Through characterization of the tuning knobs of bead size, deposition temperature and cycle count, and annealing conditions, we can create an electrically- and plasmonically-active photonic crystal as-desired for a particular application of choice.
表面等离子体激元已在等离子体和纳米光子器件中得到广泛应用。等离子体激元与三维光子晶体的结合在高表面积光电极中实现光的高效局域化方面具有巨大潜力。然而，传统上用于等离子体激元的金属难以形成三维周期性结构，并且在工作频率下的光学穿透深度有限，这限制了它们在纳米制造的光子晶体器件中的应用。近十年来，由于导电陶瓷具有提高稳定性的潜力，等离子体激元材料组合已扩展到导电陶瓷领域，并且通过原子层沉积实现其保形生长也已得到证实。在这项工作中，我们创建了具有超薄等离子体氮化钛涂层的三维光子晶体，该涂层保留了光子活性。等离子体氮化钛增强了光电极内的光场，同时保持了足够的光穿透率。此外，我们表明生长后退火可以调节氮化钛的等离子体共振，使其与光子共振重叠，这可能为这些三维纳米光子系统实现耦合现象应用。通过对珠子尺寸、沉积温度和循环次数以及退火条件等调节旋钮的表征，我们可以根据特定应用需求创建出具有电学和等离子体活性的光子晶体。
