This chapter reviews specific studies to demonstrate the advantages of refined, diverse, and synergistic ways in which device performance may be controlled through full quantum effects. These devices include: two-dimensional material (e.g., graphene, monolayer hexagonal boron nitride) for hydrogen isotope separation, ultra-sensitive quantum tunneling devices for detection, single-photon emitters, nano-cavities, high-efficiency solid-state neutron detectors, ferroelectric functional devices, and low-dimensional semiconductor devices. Nuclear quantum effect is shown to: enlarge hydrogen conductivity, enabling efficient isotope separation based on conductivity difference; engineering material with desired bandgap, facilitating the highly accurate control of quantum tunneling as well as photon absorption and emission; profoundly influence spontaneous ferroelectric polarization, dielectric constant, and polarization switching temperature, assisting functional ferroelectric devices; significantly alter electronic structure, particularly in 2D semiconductor due to spatial confinement of electron. On the other hand, studying nonadiabatic dynamics of electron–phonon coupling and photocarriers can introduce new device design parameters which achieves ultra-sensitive operation, such as chirality selectivity. From these explorations it is evident that full quantum effects not only help us discover new physical and chemical phenomena in condensed matter systems but also offer opportunities to explore novel functional materials.