▎ 摘　　要

Graphene devices are susceptible to the surrounding environment. For example, the substrate in contact with graphene influences the device performance because the carriers are confined in two-dimensional (2D) atomic thickness. However, 2D van der Waals dielectric materials used as an interface modifier can provide a path to improve the device quality. In this paper, we report enhanced mobility of up to 540 000 cm2 V-1 s-1 in monolayer graphene sandwiched between two layers of a CrOCl insulator through a dielectric shielding effect. The Shubnikov-de Haas quantum oscillation is also observed with the amplitude linearly decreasing with increasing temperature, consistent with the standard Lifshitz-Kosevich theory. More strikingly, this oscillation persists to a temperature as high as 100 K because of this enhanced mobility. Our work paves a way to improve the mobility of graphene and realize the nontrivial quantum states at high temperatures for the exploration of low-power-consumption device applications in electronics.