Acousto-Drag Photovoltaic Effect by Piezoelectric Integration of Two-Dimensional Semiconductors
Jiaming Gu, Yicheng Mou, Jianwen Ma, Haonan Chen, Chuanxin Zhang, Chuanxin Zhang, Yuxiang Wang, Jiayu Wang, Hangwen Guo, Wu Shi, Xiang Yuan, Xue Jiang, Dean Ta, Jian Shen, Cheng Zhang, Cheng Zhang
Abstract
Light-to-electricity conversion is crucial for energy harvesting and photodetection, requiring efficient electron–hole pair separation to prevent recombination. Traditional junction-based mechanisms using built-in electric fields fail in nonbarrier regions. Homogeneous material harvesting under a photovoltaic effect is appealing but is only realized in noncentrosymmetric systems via a bulk photovoltaic effect. Here we report the realization of a photovoltaic effect by employing surface acoustic waves (SAWs) to generate zero-bias photocurrent in the conventional layered semiconductor MoSe 2 . SAWs induce periodic modulation to electronic bands and drag the photoexcited pairs toward the traveling direction. The photocurrent is extracted from a local barrier. The separation of generation and extraction processes suppresses recombination and yields a large nonlocal photoresponse. We distinguish the acousto-electric drag and electron–hole pair separation effect by fabricating devices of different configurations. The acousto-drag photovoltaic effect, enabled by piezoelectric integration, offers an efficient light-to-electricity conversion method, independent of semiconductor crystal symmetry.