Molecular modeling of the electronic structure of nanomaterials in Gaussian software

Nikonorov N.Yu., Zhukalin D.A.

Voronezh State University

To study the electronic structure of both the basic and excited, often short-lived, states of molecules, quantum mechanical modeling is used in special software systems. In the case of a correctly chosen modeling method, the data obtained as a result of numerical calculations are in good agreement with the experimental results. One of the most common software packages is Gaussian. The main features are modeling electronic structures of molecules, clusters, biological compounds; modeling of periodic systems, such as polymers and crystals, by using periodic boundary conditions; modeling a wide range of spectra and spectroscopic properties of molecules; calculation of bond energy and reaction paths: modeling the properties of molecules in solutions [1].

Recently, there has been a tendency towards a transition to non-silicon electronics [2]. So, silicon carbide is considered as an alternative to silicon in power and some areas of microwave electronics. Interest in this semiconductor compound is determined by high mechanical strength, a wide range of operating temperatures, a high Debye temperature (~ 1200 ° C), and the presence of intrinsic oxide (SiO2).

Silicon carbide in these areas of electronics is gradually replacing silicon devices with more attractive electrophysical characteristics, and the unique properties of this compound allow the creation of new types of sensors and sensors.

In this work, the methods of quantum chemistry are used to study the electronic structure of 2D SiC allotropes with the number of layers n = 1-3. It has been established that 2D structures of silicon carbide form a family of semiconductor materials with a band gap from 1.132 to 2.150 eV, and layer-by-layer growth of structures determines a change in the type of conductor from direct-gap single-layer SiC to indirect-gap with the number of layers n = 2, 3. The exception is metastable structures with a width direct-gap transition 1.339 and 1.132 eV.

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