Two-dimensional (2D) ferroelectric materials have attracted intensive attention in recent years for academic research. However, the synthesis of large-scale 2D ferroelectric materials for electronic applications is still challenging. Here, we report the successful synthesis of centimeter-scale ferroelectric In2Se3 films by selenization of In2O3 in a confined space chemical vapor deposition method. The as-grown homogeneous thin film has a uniform thickness of 5 nm with robust out-of-plane ferroelectricity at room temperature. Scanning transmission electron microscopy and Raman spectroscopy reveal that the thin film is 2H stacking α-In2Se3 with excellent crystalline quality. Electronic transport measurements of In2Se3 highlight the current–voltage hysteresis and polarization modulated diode effect due to the switchable Schottky barrier height (SBH). First-principles calculations reveal that the polarization modulated SBH is originated from the competition between interface charge transfer and polarized charge. The large area growth of epitaxial In2Se3 opens up potential applications of In2Se3 in novel nanoelectronics.

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Hexagonal boron nitride (h-BN) has emerged as one of the most promising candidates for two-dimensional (2D) materials due to its exciting optoelectrical properties and a broad range of applications. In this work, we explore the potential applications of h-BN nanosheets and nanoribbons as wide band gap semiconductors in terms of carrier mobility. Based on the first-principles calculations and deformation potential (DP) theory, the phonon-limited carrier mobility of monolayer h-BN and nanoribbons at room temperature is predicted. We find that the hole mobility of armchair-edge h-BN nanoribbons (ABNNRs) oscillates regularly with the ribbon width N ac in 1–3 nm. The ABNNRs in the N ac = 3p + 1 family have larger hole mobility with the highest value of 1.9 × 104 cm2 V–1 s–1 in the narrow nanoribbons. Molecular orbital analyses reveal that the large hole mobility originates from the delocalization of the occupied orbitals of valence electrons in the transport direction. By studying the effect of ribbon width on mobility, we identify the role of quantum confinement in tuning the transport properties of h-BN nanoribbons. The potential technological application of h-BN nanostructures as a P-channel material in wide band gap 2D field effect transistors (FETs) is discussed.