An ultrasensitive molybdenum-based double-heterojunction phototransistor

• Published in: Nature communications Vol. 12; no. 1; pp. 4094 - 8
• Main Authors: Feng, Shun, Liu, Chi, Zhu, Qianbing, Su, Xin, Qian, Wangwang, Sun, Yun, Wang, Chengxu, Li, Bo, Chen, Maolin, Chen, Long, Chen, Wei, Zhang, Lili, Zhen, Chao, Wang, Feijiu, Ren, Wencai, Yin, Lichang, Wang, Xiaomu, Cheng, Hui-Ming, Sun, Dong-Ming
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 02.07.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/1005/1007; 639/301/357/1018; Electrodes; Fabrication; Heterojunctions; Humanities and Social Sciences; Hybrid structures; Molybdenum; Molybdenum disulfide; Molybdenum trioxide; multidisciplinary; Noise generation; Optical properties; Photosensitivity; Phototransistors; Positive feedback; Science; Science (multidisciplinary); Strong interactions (field theory); Two dimensional materials
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-24397-x

Two-dimensional (2D) materials are promising for next-generation photo detection because of their exceptional properties such as a strong interaction with light, electronic and optical properties that depend on the number of layers, and the ability to form hybrid structures. However, the intrinsic detection ability of 2D material-based photodetectors is low due to their atomic thickness. Photogating is widely used to improve the responsivity of devices, which usually generates large noise current, resulting in limited detectivity. Here, we report a molybdenum-based phototransistor with MoS 2 channel and α-MoO 3-x contact electrodes. The device works in a photo-induced barrier-lowering (PIBL) mechanism and its double heterojunctions between the channel and the electrodes can provide positive feedback to each other. As a result, a detectivity of 9.8 × 10 16  cm Hz 1/2 W −1 has been achieved. The proposed double heterojunction PIBL mechanism adds to the techniques available for the fabrication of 2D material-based phototransistors with an ultrahigh photosensitivity. Here, the authors exploit a photo-induced barrier-lowering mechanism in MoS 2 / α-MoO 3-x heterojunctions to realize two-dimensional phototransistors with enhanced performance and fast response at low bias voltage.