High electron mobility in well ordered and lattice-strained hydrogenated nanocrystalline silicon

We report on the realization of high electron mobility (over 103 cm2 V−1 s−1) in structure-ordered and lattice-strained hydrogenated nanocrystalline silicon (nc-Si:H) due to the decrease of conduction effective mass and phonon scattering. The nc-Si:H thin films were grown on crystalline silicon substrates by plasma-enhanced chemical vapour deposition through the radio-frequency power to properly control the chemical reactions of H atoms with the Si–Si network. The electron mobility and concentration in the nc-Si:H have been extracted with the aid of magnetic-field-dependent Hall effect measurements. X-ray diffraction, Raman, and infrared transmission experiments have been employed to yield information about the lattice strain and structural order in the Si nanocrystals. The room-temperature experimental mobility has been well explained by a generalized Drude transport model unifying both the diffusive and ballistic transport mechanisms.