in a silicon nanowires (SiNWs) array/TiO2/reduced graphene oxide (rGO) sensor with sensitive and selective response toward nitro‐explosives vapors. The response of the SiNWs array/TiO2/rGO sensor toward nitro‐explosives vapors, such as 9 ppb 2,4,6‐trinitrotoluene, 4.9 ppt hexogen, and 0.25 ppq octagon, is boosted by 2.4, 7.5, and 5 times with the insertion of TiO2. Superior selectivity is shown even compared with interfering gases of 10 ppm. Such good sensing performance can be attributed to the good sensing performance of the Schottky heterojunction‐based sensor, the Schottky barrier height modulation with the insertion of TiO2, SiNWs array structure enhanced diffusion, and TiO2 nanoparticles enhanced adsorption. This is believed to be the first Schottky heterojunction‐based sensor for nitro‐explosives vapors detection. This work would open a new way to develop highly sensitive and selective sensors.