The design of ultrathin semiconducting materials that achieve broadband absorption is a long‐sought‐after goal of crucial importance for optoelectronic applications. To date, attempts to tackle this problem consisted either of the use of strong—but narrowband—or broader—but moderate—light‐trapping mechanisms. Here, a strategy that achieves broadband optimal absorption in arbitrarily thin semiconductor materials for all energies above their bandgap is presented. This stems from the strong interplay between Brewster modes, sustained by judiciously nanostructured thin semiconductors on metal films, and photonic crystal modes. Broadband near‐unity absorption in Ge ultrathin films is demonstrated, which extends from the visible to the Ge bandgap in the near‐infrared and is robust against angle of incidence variation. The strategy follows an easy and scalable fabrication route enabled by soft nanoimprinting lithography, a technique that allows seamless integration in many optoelectronic fabrication procedures.

中文翻译：

---

从可见光到近红外的超薄半导体超级吸收剂

实现宽带吸收的超薄半导体材料的设计是一个长期追求的目标，对光电应用至关重要。迄今为止，解决该问题的尝试要么是使用强但窄带的信号捕获，要么是使用较宽但中度的光捕获机制。在此，提出了一种策略，该方法可在任意薄半导体材料中针对带隙以上的所有能量实现宽带最佳吸收。这源于在金属膜上明智地纳米结构化的薄半导体和光子晶体模式之间维持的布鲁斯特模式之间的强烈相互作用。演示了Ge超薄膜中宽带的近统一吸收，它从可见光延伸到近红外的Ge带隙，并且对入射角变化具有鲁棒性。