title: High-Mobility Transport Anisotropy in Few-Layer MoO3and Its Origin.
abstract: The novel two-dimensional semiconductors with high carrier mobility and excellent stability are essential to the next-generation high-speed and low-power nanoelectronic devices. Because of the natural abundance, intrinsic gap, and chemical stability, metal oxides were also recently suggested as potential candidates for electronic materials. However, their carrier mobilities are typically on the order of tens of square centimeters per volt per second, much lower than that for commonly used silicon. By using first-principles calculations and deformation potential theory, we have predicted few-layer MoO3as chemically stable wide-band-gap semiconductors with a considerably high acoustic-phonon-limited carrier mobility above 3000 cm2V-1s-1, which makes them promising candidates for both electron- and hole-transport applications. Moreover, we also find a large in-plane anisotropy of the carrier mobility with a ratio of about 20-30 in this unusual system. Further analysis indicates that, because of the unique charge density distribution of whole valence electrons and the states near the band edge, both the elastic modulus and deformation potential are strongly directionally dependent. Also, the predicted high-mobility transport anisotropy of few-layer MoO3can be attributed to the synergistic effect of the anisotropy of the elastic modulus and deformation potential. Our results not only give an insightful understanding for the high carrier mobility observed in few-layer MoO3systems but also reveal the importance of the carrier-transport direction to the device performance.
authors.affiliation: School of Physics and Electronic Sciences, Changsha University of Science and Technology , Changsha 410004, People's Republic of China.
authors.forename: Wei-Bing
authors.identifier: http://orcid.org/0000-0003-1306-4540
authors.initials: WB
authors.lastname: Zhang
authors.affiliation: School of Physics and Electronic Sciences, Changsha University of Science and Technology , Changsha 410004, People's Republic of China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Qu
authors.affiliation: School of Physics and Electronic Sciences, Changsha University of Science and Technology , Changsha 410004, People's Republic of China.
authors.forename: Kang
authors.initials: K
authors.lastname: Lai
keywords: deformation potential theory; effective mass approximation; few-layer MoO3; first-principles calculations; high mobility; transport anisotropy