اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدEffect of acetylene links on electronic and optical properties of semiconducting graphynes
66
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
The family of graphynes, novel two-dimensional semiconductors with various and fascinating chemical and physical properties, has attracted great interest from both science and industry. Currently, the focus of graphynes is on graphdiyne, or graphyne-2. In this work, we systematically study the effect of acetylene, i.e., carbon-carbon triple bond, links on the electronic and optical properties of a series of graphynes (graphyne-n, where n = 1-5, the number of acetylene bonds) using the ab initio calculations. We find an even-odd pattern, i.e., n = 1, 3, 5 and n = 2, 4 having different features, which has not be discovered in studying graphyne or graphdyine only. It is found that as the number of acetylene bonds increases, the electron effective mass increases continuously in the low energy range because of the flatter conduction band induced by the longer acetylene links. Meanwhile, longer acetylene links result in larger redshift of the imaginary part of the dielectric function, loss function, and extinction coefficient. In this work, we propose an effective method to tune and manipulate both the electronic and optical properties of graphynes for the applications in optoelectronic devices and photo-chemical catalysis.
قيم البحث
اقرأ أيضاً
We present many-body textit{ab initio} calculations of the electronic and optical properties of semiconducting zigzag carbon nanotubes under uniaxial strain. The GW approach is utilized to obtain the quasiparticle bandgaps and is combined with the Be
the-Salpeter equation to obtain the optical absorption spectrum. We find that the dependence of the electronic bandgaps on strain is more complex than previously predicted based on tight-binding models or density-functional theory. In addition, we show that the exciton energy and exciton binding energy depend significantly on strain, with variations of tens of meVs per percent strain, but that despite these strong changes the absorbance is found to be nearly independent of strain. Our results provide new guidance for the understanding and design of optomechanical systems based on carbon nanotubes.
The direct growth of graphene on semiconducting or insulating substrates might help to overcome main drawbacks of metal-based synthesis, like metal-atom contaminations of graphene, transfer issues, etc. Here we present the growth of graphene on n-dop
ed semiconducting Ge(110) by using an atomic carbon source and the study of the structural and electronic properties of the obtained interface. We found that graphene interacts weakly with the underlying Ge(110) substrate that keeps graphenes electronic structure almost intact promoting this interface for future graphene-semiconductor applications. The effect of dopants in Ge on the electronic properties of graphene is also discussed.
The electronic and optical properties of the cleavage InAs(110) surface are studied using a semi-empirical tight-binding method which employs an extended atomic-like basis set. We describe and discuss the electronic character of the surface electroni
c states and we compare with other theoretical approaches, and with experimental observations. We calculate the surface electronic band structure and the Reflectance Anisotropy Spectrum, which are described and discussed in terms of the surface electronic states and the atomic structure.
We study the effect of boron (B) and Phosphorous (P) co-doping on electronic and optical properties of graphitic carbon nitride (g-C$_3$N$_4$ or GCN) monolayer using density functional simulations. The energy band structure indicates that the incorpo
ration of B and P into a hexagonal lattice of GCN reduces the energy band gap from $3.1$ for pristine GCN to $1.9$ eV, thus extending light absorption toward the visible region. Moreover, on the basis of calculating absorption spectra and dielectric function, the co-doped system exhibits an improved absorption intensity in the visible region and more electronic transitions, which named $pi^*$ electronic transitions that occurred and were prohibited in the pristine GCN. These transitions can be attributed to charge redistribution upon doping, caused by distorted configurable B/P co-doped GCN confirmed by both electron density and Mulliken charge population. Therefore, B/P co-doped GCN is expected to be an auspicious candidate to be used as a promising photoelectrode in Photoelectrochemical water splitting reactions leading to efficient solar H$_2$ production.
The phonon properties, electronic structures and optical properties of novel carbon allotropes, such as monolayer penta-graphene (PG), double-layer PG and T12-carbon, were explored by means of first-principles calculations. Results of phonon calculat
ions demonstrate that these exotic carbon allotropes are dynamically stable. In addition, the bulk T12 phase is an indirect-gap semiconductor having a bandgap of ~4.89 eV. Whereas the bulk material transforms to a 2D phase, the monolayer and double-layer PG become quasi-direct gap semiconductors with smaller band gaps of ~2.64 eV and ~3.27eV, respectively. Furthermore, the partial charge density analysis indicates that the 2D phases retain part of the electronic characteristics of the T12 phase. The linear photon energy-dependent dielectric functions and related optical properties including refractive index, extinction coefficient, absorption spectrum, reflectivity, and energy loss spectrum were also computed and discussed. The structural estimation obtained as well as other findings are in agreement with existing theoretical data. The calculated results are beneficial to the practical applications of these exotic carbon allotropes in optoelectronics and electronics.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
