Tensile strain induced enhancement of the electron transport in polar two-dimensional (2D) InN

Abstract

Two-dimensional (2D) semiconductors have been regarded as promising candidates for next-generation nanoelectronics devices. However, the intrinsically low carrier mobility severely limits device performance. In this work, we have systematically investigated the carrier transport in 2D hexangular InN based on the ab initio Boltzmann transport theory. The room-temperature carrier mobility is evaluated over a wide range of carrier concentration (n2D), with the free-carrier screening effect incorporated via the 2D homogeneous electron gas model. The high intrinsic electron mobility of InN is verified. At low n2D, the electron mobility remains nearly a constant of 790 cm2 V−1s−1, whereas a peak value of 1150 cm2 V−1s−1 is observed at high n2D. Our mode-by-mode analysis of the scattering events demonstrates that the long-range electron–phonon couplings govern the electron transport. The high electron mobility is attributed to the exceptionally small effective masses in combination with the significant suppression of LO-phonon scattering. Furthermore, we show that applying biaxial tensile strain can significantly enhance the electron transport. At low n2D = 1 × 1010 cm−2, 3% tensile strain makes the mobility increase by 186%. The further analysis has demonstrated that the mobility enhancement results from the increased band velocity and the reduced scattering rates. Our work not only sheds light on the carrier transport in 2D InN but also underscores its great promise for high-performance electronic devices. Moreover, the provided estimation of the gauge factor highlights the potential for strain-sensing applications.