摘要： In present work, we introduce the controlled synthesis of few layer vertically oriented MoS2 flakes for high performance NO2 gas sensor applications. The density and the thickness of MoS2 nanosheets are controlled by varying the heating rate of the chemical vapor deposition process. Our study confirms that the nanoflakes of about three layers were obtained under the heating rate of 5 oC by using powders of MoO3 and S as precursors without using any catalyst. This is very advantageous because no catalyst was used, there was 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 demonstrated that the interconnected vertically oriented MoS2 nanoflakes have a good response value of 20.1% to 0.5 ppm NO2 at RT, and 1.73% at 150 oC. The sensor showed full recovery characteristic at a measured temperature of 150 oC with response and recovery time of about 15 s, and 100 s, respectively. The sensor also exhibited good selectivity with the ignorable response to SO2, H2, NH3, H2S and a low detection limit of 42 ppb.