2D SnSe/Si heterojunction for self-driven broadband photodetectors

• Published in: 2d materials Vol. 6; no. 3; pp. 34004 - 34013
• Main Authors: Hao, Lanzhong, Wang, Zegao, Xu, Hanyang, Yan, Keyou, Dong, Shichang, Liu, Hui, Du, Yongjun, Wu, Yupeng, Liu, Yunjie, Dong, Mingdong
• Format: Journal Article
• Language: English
• Published: IOP Publishing 02.05.2019
• Subjects: broadband; heterojunction; photodetector; self-driven; tin monoselenide
• ISSN: 2053-1583; 2053-1583
• DOI: 10.1088/2053-1583/ab15f7

Van der Waals heterojunctions based on atomically thin 2D materials have opened up new realms in modern semiconductor industry. However, it is still challenging to fabricate large-area ultrathin 2D films. Herein, we successfully fabricate wafer-size 2D SnSe films on Si substrate by magnetron sputtering technique, enabling the formation of SnSe/Si van der Waals (vdWs) heterojunction device. The high-resolution transmission electron microscopy is employed to character the structure of SnSe film and SnSe/Si heterojunction with ideal orthorhombic structure and atomically abrupt interface, respectively. The energy diagram of SnSe/Si heterojunction is constructed, exhibiting similar barrier heights for electron and hole carrier. The SnSe/Si heterojunction shows obvious diode behavior with rectification ratio of ~1.6  ×  104, forward current of ~194.5 mA cm−2 at  ±1.0 V. Furthermore, owing to the high crystalline orientation, specific energy-band alignment, as well as the strong built-in electrical field, the SnSe/Si heterojunction illustrates a broadband photodetecting properties with the wavelength ranging from ultraviolet to near-infrared light, showing a high detectivity of 4.4  ×  1012 cmHz1/2 W−1, a high responsivity of 566.4 mA mW−1 and an ultrafast response/recovery time of ~1.6/47.7 µs under zero external bias. This work provides a new strategy for fabrication of low cost 2D optoelectronic devices with high-performance.