Our density functional calculations show that opening a sizeable band gap of silicene without degrading its carrier mobility can be realized by silicene–substrate hybrid structures with noncovalent interface interactions. Several possible two-dimensional semiconducting substrates are selected to find the factors that control the magnitude of band gap. It is found that the more notable charge redistribution in two sublattices of silicene and thus a larger band gap are characterized by a smaller interlayer distance. Thus, the opened band gap in hybrid structures with SiH/π interaction has reached the technique requirement of room-temperature operation in field effect transistors.