Chen Mengping, Chen Yingliang, Yang Guang, Wang Qiwen, Feng Xiaobo
School of Physics and Electronic Information, Yunnan Normal University, Kunming 650500, China.
Yunnan Key Laboratory of Opto-Electronic Information Technology, Yunnan Normal University, Kunming 650500, China.
Nanomaterials (Basel). 2025 Feb 23;15(5):345. doi: 10.3390/nano15050345.
We theoretically investigate the comprehensive modulation effect of interlayer twisting and external electric field to the two-photon absorption (TPA) in twisted graphene/hexagonal boron nitride (tG/hBN) heterojunction with small twist angles (2° < θ < 10°) starting from an effective continuum model. It is found that the TPA of tG/hBN is extended to the visible light band from infrared light band of that in twisted bilayer graphene (tBLG) due to the increase in energy band gap caused by twisting and the potential energy of the boron nitride atomic layer. And the TPA coefficient is enhanced several times via an external electric field, which increases the density of states, leading to an increase transition probability for two-photon absorption.
我们从一个有效的连续模型出发，从理论上研究了层间扭曲和外部电场对小扭曲角（2°<θ<10°）的扭曲石墨烯/六方氮化硼（tG/hBN）异质结中双光子吸收（TPA）的综合调制效应。研究发现，由于扭曲导致的能带隙增加以及氮化硼原子层的势能，tG/hBN的TPA从扭曲双层石墨烯（tBLG）的红外光带扩展到可见光带。并且通过外部电场，TPA系数提高了几倍，这增加了态密度，导致双光子吸收的跃迁概率增加。
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