Wafer-scaled SnSe₂ fabricated by plasma assisted selenization and the ppb-level NOx sensing at room temperature

Tzu Wen Kuo^1*, Hong min Wu², Kai Chen¹, Wang-Kuang Ye¹, Ling Lee¹, Yu-Lun Chueh¹

¹Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan
²Institute of Electronics Engineering, National Tsing Hua University, Hsinchu, Taiwan

* Presenter:Tzu Wen Kuo, email:twkuo920@gmail.com

Highly sensitive gas-sensing devices based on SnSe₂ that underwent at room temperature against NOx with a limit of detection of 18 ppb are demonstrated in this paper. A method of using plasma assisted chemical vapor reaction (PACVR) was achieved to synthesize SnSe₂ at a temperature as low as 250°C, for which the growth on a SiO₂/Si wafer and even a soft polyimide (PI) substrate was succeeded. In this work, the dependence of gas sensing performance on the thickness was studied. When the thicknesses of SnSe₂ thin films decreased, the response of SnSe₂ gas sensor increased. It is worth noticing that an estimated detection limit of detection against NO₂ of 18 ppb at room temperature was achieved at a thickness of 10 nm. Also, SnSe₂ showed high selectivity against NOx among various target gases.

Keywords: SnSe₂, plasma assisted chemical vapor reaction, NOx, ppb