Search

2D semiconductor field‐effect transistors (2D FETs) have emerged as a promising candidate for beyond‐silicon electronics applications. However, its device performance has often been limited by the metal‐2D semiconductor contact, and the non‐negligible contact resistance (RSD) not only deteriorates the on‐state current but also hinders the direct characterization of the intrinsic properties of 2D semiconductors (e.g., intrinsic charge carrier mobility, μint). Therefore, a proper extraction technique that can independently characterize the metal‐2D semiconductor contact behavior and the intrinsic properties of a 2D semiconducting layer is highly desired. In this study, a universal yet simple method is developed to accurately extract the critical parameters in 2D FETs, including characteristic temperature (To), threshold voltage (VT), RSD, and μint. The practicability of this method is extensively explored by characterizing the temperature‐dependent carrier transport behavior and the strain‐induced band structure modification in 2D semiconductors. Technology computer aided design simulation is subsequently employed to verify the precision of RSD extraction. Furthermore, the universality of the proposed method is validated by successfully implementing the extraction to various 2D semiconductors, including black phosphorus, indium selenide, molybdenum disulfide, rhenium disulfide, and tungsten disulfide with top‐ and bottom‐gated configurations. [ABSTRACT FROM AUTHOR]

Unceasing efforts have been devoted to photonics based on black phosphorus ever since it came under the spotlight of two-dimensional materials research six years ago. The direct bandgap of black phosphorus is tunable by layer number, vertical electric field, and chemical doping, covering a broad spectrum for efficient light manipulation. The optical anisotropy further enables the identification and control of light polarization. Along with high carrier mobility, nonlinear optical properties, and integration capability due to its layered lattice structure, black phosphorus manifests itself as a promising multipurpose material for chip-scale optoelectronics. In this manuscript, we review the research on black phosphorus photonics, with a focus on the most fundamental active functions in photonic circuits: photodetection, electro-optic modulation, light emission, and laser pulse generation, aiming at evaluating the feasibility of integrating these black phosphorus-based components as a compact system for on-chip applications. [ABSTRACT FROM AUTHOR]

Substitutional and adatom impurity doping can be considered quite effective or even better for modulating the electronic transport coefficients. Herein, we have studied the impact of substitutional doping by Al and Cl multi atoms and adatom adsorption by O, Cu, K, and Ag atoms on the electronic transport properties of single-layer black phosphorus using the first-principles method based density functional theory framework in conjunction with Boltzmann transport equation at room temperature. We found that these impurity atoms introduce new donor and acceptor induced eigenstates and flat bands within the fundamental bandgap. We have calculated the scattering rates and relaxation time by solving the Boltzmann transport equation with the ab-initio calculated electron-phonon interactions. The electron-phonon coupling matrix elements are computed through maximally localized Wannier functions and density functional perturbation theory using Wannier-Fourier interpolation on a fine sampling of the Brillouin zone. The binding energies illustrated the structural stability of all doped systems and found that phosphorene showed a stronger adsorption capability as compared with the graphene and MoS 2 sheet. Moreover, binding energy for the substitutionally doped system is found to decrease with the increasing atomic number. Furthermore, the achieved electron mobility, electrical conductivity (σ), and Seebeck coefficient (S) of pristine single-layer black phosphorus are ~279 cm2V−1s−1, 6.1 × 106 Ω−1m−1 and 1.4 mV/K respectively. The calculated values of carrier mobility, electrical conductivity and Seebeck coefficient have found a rich diversity in each impurity doped layer, and the negative differential behaviour is observed. These results provide comprehensive information about chemical functionalization and bandgap tunability for modelling of phosphorene based devices. • Substitutional and adatom impurity doping are effective for modulating the electronic transport coefficients of phosphorene. • We have studied the impact of substitutional doping by Al and Cl multi atoms and adatom adsorption by O, Cu, K, and Ag atoms. • We have calculated the scattering rates and relaxation time by solving the Boltzmann transport equation. • The binding energies illustrated the structural stability and found that phosphorene showed a stronger adsorption capability. • The calculated values of carrier mobility, electrical conductivity and Seebeck coefficient have found a rich diversity. [ABSTRACT FROM AUTHOR]