Ab initio prediction of semiconductivity in a novel two-dimensional Sb2X3 (X= S, Se, Te) monolayers with orthorhombic structure

Sb 2S 3 and Sb 2Se 3 are well-known layered bulk structures with weak van der Waals interactions. In this work we explore the atomic lattice, dynamical stability, electronic and optical properties of Sb 2S 3, Sb 2Se 3 and Sb 2Te 3 monolayers using the density functional theory simulations. Molecular dynamics and phonon dispersion results show the desirable thermal and dynamical stability of studied nanosheets. On the basis of HSE06 and PBE/GGA functionals, we show that all the considered novel monolayers are semiconductors. Using the HSE06 functional the electronic bandgap of Sb 2S 3, Sb 2Se 3 and Sb 2Te 3 monolayers are predicted to be 2.15, 1.35 and 1.37 eV, respectively. Optical simulations show that the first absorption coefficient peak for Sb 2S 3, Sb 2Se 3 and Sb 2Te 3 monolayers along in-plane polarization is suitable for the absorption of the visible and IR range of light. Interestingly, optically anisotropic character along planar directions can be desirable for polarization-sensitive photodetectors. Furthermore, we systematically investigate the electrical transport properties with combined first-principles and Boltzmann transport theory calculations. At optimal doping concentration, we found the considerable larger power factor values of 2.69, 4.91, and 5.45 for hole-doped Sb 2S 3, Sb 2Se 3, and Sb 2Te 3, respectively. This study highlights the bright prospect for the application of Sb 2S 3, Sb 2Se 3 and Sb 2Te 3 nanosheets in novel electronic, optical and energy conversion systems. © 2021, The Author(s)

Response to Comment on (Novel two-dimensional porous graphitic carbon nitride C6N7 monolayer: A First-principle calculations [Appl. Phys. Lett. 2021, 119, 142102])

Recently, reported a comments on the our paper [Appl. Phys. Lett. 119, 142102 (2021)]. With our response, the APL journal rejected their non scientific comments. There are some ambiguities about their claim: 1-They can check the phonon dispersion of their structure to see ZA out-of-plane mode. 2-They report the uniaxial stress-strain responses in Fig 2., which is unrelated to our paper. For a more helpful understanding of the mechanical properties of the novel C6N7 monolayer, they can publish a paper. 3-They mentioned: Using the DFT method and with assuming a thickness of 3.35 A for the C6N7 monolayer based on graphene thickness. Why did they choose this thickness while we know our C6N7 monolayer is at without buckling? The distance of ZA out-of-plane movement of ions in C6N7 is different from Graphene.Comment: 1 pag

CONTROL SYSTEM OF 10-MEV BABY CYCLOTRON

Abstract For controlling all the equipment and services required for operating the 10 MeV baby cyclotron and optimizing various parameters, an extensive control system is used

Electromagnetic design and optimization of the multi-segment dielectric-loaded accelerating tube using genetic algorithm

A low-energy dielectric loaded accelerator with a non-uniform, multi-segment structure is studied and optimized. So far, no analytical solution is provided for such structures. Also, due to the existing nonlinear behavior and a large number of geometric parameters, the problem of numerical optimizations is complex. For this reason, a method is presented to design and optimize such structures using the Genetic Algorithm (GA). Moreover, the GA output results are compared with Trust Region (TR) and Nelder-Mead Simplex (NMS) methods. Comparative results show that the GA is more efficient in achieving optimization goals and also has a higher speed than the two other methods. Finally, an optimized accelerating tube is integrated into a proper coupler. Then, the accelerator is simulated for full electromagnetic investigations using the CST suite of codes. This design leads to a structure with a power of about 80 kW in the X-band, which delivers electrons to the output energy in the range of 300–459 kV. The length and outer diameter of the accelerating tube obtained are 10 cm and 1 cm, respectively