The controlled synthesis of few‐layer vertically oriented MoS₂ flakes for high‐performance NO₂ gas sensor applications is introduced. The density and the thickness of MoS₂ nanosheets are controlled by varying the heating rate of the chemical vapor deposition process. Herein, it is confirmed that the nanoflakes of about three layers are obtained under the heating rate of 5 °C using powders of MoO₃ and S as precursors without using any catalyst. This is very advantageous because no catalyst is used, there is no need of buffer layer at the bottom of the MoS₂ thin‐film flacks, thus omitting the leakage current when measuring the electrical signal and enhancing the gas sensing performance. Gas sensing measurements demonstrate that the interconnected vertically oriented MoS₂ nanoflakes have a good response value of 20.1% to 0.5 ppm NO₂ at room‐temperature (RT), and 1.73% at 150 °C. The sensor shows full recovery characteristic at a measured temperature of 150 °C with response and recovery time of about 15 and 100 s, respectively. The sensor also exhibits good selectivity with the ignorable response to SO₂, H₂, NH₃, H₂S, and a low detection limit of 42 ppb.

中文翻译：

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用于室温NO2气体传感器应用的垂直取向三层MoS2纳米薄片的受控生长

介绍了用于高性能NO ₂气体传感器应用的多层垂直取向MoS ₂薄片的可控合成。通过改变化学气相沉积过程的加热速率来控制MoS ₂纳米片的密度和厚度。在本文中，证实了在5℃的加热速率下使用MoO ₃和S的粉末作为前体而不使用任何催化剂，获得了大约三层的纳米薄片。这是非常有利的，因为不使用催化剂，在MoS ₂的底部不需要缓冲层薄膜斑点，因此在测量电信号时可以省去泄漏电流，并增强气体感应性能。气敏测量表明，相互连接的垂直取向的MoS ₂纳米薄片在室温（RT）下具有20.1％至0.5 ppm NO ₂的良好响应值，在150°C下具有1.73％的良好响应值。传感器在150°C的测量温度下显示完全恢复特性，响应时间和恢复时间分别约为15 s和100 s。该传感器还具有对SO ₂，H ₂，NH ₃，H ₂ S的可忽略响应的良好选择性，并且检测限低至42 ppb。