Two-step fabrication of single-layer rectangular SnSe flakes

• Published in: 2d materials 2017-04, Vol.4 (2), p.21026
• Main Authors: Jiang, Jizhou, Wong, Calvin Pei Yu, Zou, Jing, Li, Shisheng, Wang, Qixing, Chen, Jianyi, Qi, Dianyu, Wang, Hongyu, Eda, Goki, Chua, Daniel H C, Shi, Yumeng, Zhang, Wenjing, Wee, Andrew Thye Shen
• Format: Article
• Language: English
• Subjects: large-sized single-layer; nitrogen etching technique; rectangular SnSe flakes; vapor transport deposition
• ISSN: 2053-1583; 2053-1583
• DOI: 10.1088/2053-1583/aa6aec

Recent findings about ultrahigh thermoelectric performances in SnSe single crystals have stimulated research on this binary semiconductor material. Furthermore, single-layer SnSe is an interesting analogue of phosphorene, with potential applications in two-dimensional (2D) nanoelectronics. Although significant advances in the synthesis of SnSe nanocrystals have been made, fabrication of well-defined large-sized single-layer SnSe flakes in a facile way still remains a challenge. The growth of single-layer rectangular SnSe flakes with a thickness of ~6.8 Å and lateral dimensions of about 30 µm  ×  50 µm is demonstrated by a two-step synthesis method, where bulk rectangular SnSe flakes were synthesized first by a vapor transport deposition method followed by a nitrogen etching technique to fabricate single-layer rectangular SnSe flakes in an atmospheric pressure system. The as-obtained rectangular SnSe flakes exhibited a pure crystalline phase oriented along the a-axis direction. Field-effect transistor devices fabricated on individual single-layer rectangular SnSe flakes using gold electrodes exhibited p-doped ambipolar behavior and a hole mobility of about 0.16 cm2 V−1 s−1. This two-step fabrication method can be helpful for growing other similar 2D large-sized single-layer materials.