Chen Huiying, Zheng Yingshuang, Jin Chunqi, Tan Fan, Yu Jiaqi, He Ting, Wang Peng, Liang Hongwei, Wei Jingxuan, Li Longnan
Opt Lett. 2025 Jan 1;50(1):85-88. doi: 10.1364/OL.542894.
The bulk photovoltaic effect (BPVE) and its artificial variant generate photocurrent under zero external bias in non-centrosymmetric systems, particularly in on-chip miniaturized metasurface-based photodetectors. Despite significant advancements, enhancing the efficiency of local photocurrent collection remains a challenge, often impeded by non-uniform flow fields in graphene caused by nanoantenna contacts, which lead to carrier transport losses. In this study, we conducted a comprehensive investigation into the regulation of local photocurrent collection in zero-bias optoelectronic metasurface-based photodetectors and explored the impact of nanoantenna array configurations on photocurrent efficiency. Using a multi-layer graphene-based photodetector with V-shaped nanoantennas, we found that configuring the array layout - specifically, adopting a 5 × 5 configuration - significantly enhances responsivity, achieving an impressive 21.6 mA/W at zero bias with a considerable photocurrent of 129 nA. Through photocurrent mapping and analysis based on the Schottky-Ramo theorem, we demonstrated that non-uniform flow fields induced by nanoantenna contacts hinder local carrier transport.
体光伏效应（BPVE）及其人工变体在非中心对称系统中，特别是在基于片上微型超表面的光电探测器中，能在零外部偏压下产生光电流。尽管取得了显著进展，但提高局部光电流收集效率仍然是一个挑战，这通常受到纳米天线接触导致的石墨烯中不均匀流场的阻碍，从而导致载流子传输损耗。在本研究中，我们对基于零偏压光电超表面的光电探测器中局部光电流收集的调控进行了全面研究，并探讨了纳米天线阵列配置对光电流效率的影响。使用具有V形纳米天线的多层石墨烯基光电探测器，我们发现配置阵列布局——具体而言，采用5×5配置——可显著提高响应度，在零偏压下实现了令人印象深刻的21.6 mA/W的响应度以及可观的129 nA光电流。通过基于肖特基 - 拉莫定理的光电流映射和分析，我们证明了纳米天线接触引起的不均匀流场阻碍了局部载流子传输。
