Controlled Growth of a Large-Size 2D Selenium Nanosheet and Its Electronic and Optoelectronic Applications

5 years ago

Controlled Growth of a Large-Size 2D Selenium Nanosheet and Its Electronic and Optoelectronic Applications

Peide D. Ye, Xianfan Xu, Lingming Yang, Adam Charnas, Gang Qiu, Dmitry Y. Zemlyanov, Cheng-Yan Xu, Jingkai Qin, Jie Jian, Wenzhuo Wu, Hong Zhou, Haiyan Wang

Selenium has attracted intensive attention as a promising material candidate for future optoelectronic applications. However, selenium has a strong tendency to grow into nanowire forms due to its anisotropic atomic structure, which has largely hindered the exploration of its potential applications. In this work, using a physical vapor deposition method, we have demonstrated the synthesis of large-size, high-quality 2D selenium nanosheets, the minimum thickness of which could be as thin as 5 nm. The Se nanosheet exhibits a strong in-plane anisotropic property, which is determined by angle-resolved Raman spectroscopy. Back-gating field-effect transistors based on a Se nanosheet exhibit p-type transport behaviors with on-state current density around 20 mA/mm at V_ds = 3 V. Four-terminal field-effect devices are also fabricated to evaluate the intrinsic hole mobility of the selenium nanosheet, and the value is determined to be 0.26 cm² V^–1 s^–1 at 300 K. The selenium nanosheet phototransistors show an excellent photoresponsivity of up to 263 A/W, with a rise time of 0.1 s and fall time of 0.12 s. These results suggest that crystal selenium as a 2D form of a 1D van der Waals solid opens up the possibility to explore device applications.

Publisher URL: http://dx.doi.org/10.1021/acsnano.7b04786

DOI: 10.1021/acsnano.7b04786