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2nd Edition of International Conference on

Materials Science and Engineering

March 28 -30, 2022 | Singapore

2022 Speakers

Physical and Chemical Properties of Optoelectronic Materials with sphalerite and wurtzite structure

V P Vassiliev, Speaker at Speaker at Materials Conferences: V P Vassiliev
Lomonosov Moscow State University, Russian Federation
Title : Physical and Chemical Properties of Optoelectronic Materials with sphalerite and wurtzite structure

Abstract:

There are the strict relationships between the physical and chemical properties of isostructural compounds and the Periodic Law. The systematization of this data vs. the Periodic Law, will contribute to further development of the solid state chemistry theory. Our previous review articles [1,2] evidenced the relation of thermodynamic data with Periodic Law and established relationship between the enthalpy of formation, melting point and the atomic numbers of components in the semiconductor AIIIBV phases, with diamond-like structure of sphalerite and wurtzite types. The proposed model was used for the critical assessment of the thermodynamic properties of isostructural compounds. The relationship between the reduced enthalpy (), standard entropy (), reduced Gibbs energy and the sum of the atomic numbers (Zi = ZA + ZB) has been used for a critical assessment of the thermodynamic properties of AIIIBV and AIIBVI phases. The Similarity Method was used for the critical analysis of specific heats  the fourth group of pure elements and AIIIBV and AIIBVI diamond-like isostructural phases in solid state. A critical analysis of heat capacities was carried out for the pure elements of the Periodic System fourth group (C, Si, Ge, Sn) and isostructural phases AIIIBV and AIIBVI. It was found that the dependence of the heat capacities  from 0 to melting point follows strict regularity. Phases with the same sum of atomic numbers of elements (Zi), such as BN (hex) Zi = 12 and glassy pure carbon Z = 6; BP and AlN (Zi = 20); AlP (Zi = 28) and pure Si (Z = 14); BAs and GaN (Zi = 38); AlAs and ZnS (Zi = 46); AlSb, GaAs, InP, CdS (Zi = 64) and pure Ge (Z = 32); GaSb, InAs, and CdSe (Zi = 82); InSb, CdTe (Zi = 100) and pure gray Sn (Z= 50); have the same heat capacity experimental values in the solid state within the experimental uncertainty [3]. The fourth group of pure diamond-like elements include, in addition to diamond, silicon, germanium, alpha tin, and diamond-like lead [4]. Flerovium (114Fl) closes this group. There should be no other elements in this group according to the fine structure constant or the Sommerfeld constant α = e2 / ?c.The parameter α is a dimensionless quantity, and its numerical value is close to 1/137. This constant allows us to determine that with the highest probability, the last neutral atom of the periodic table will be element 137. In the case of diamond-like phases with a wurtzite structure, the limiting value of the heat capacity ?? falls on 114 elements (114Fl) and has 30.5065 J mol-at-1 K-1 = 3.67 R or Ln (Cp/R) = 1.3. In the case of AlN (wurtzite structure) the Cp value is in the range of 3.7 R - 3.8 R J mol-at-1 K-1 [2] at a temperature close to Tm = 4840 ±50K. It can be assumed that the maximum Cp of any solid at a temperature close to Tm does not exceed 4R =33.256 J mol-at-1K-1. The heat capacities of Si, Ge, HgTe compound and the virtual point of flerovium were used as the main reference points of the isotherms. This method permits to calculate  of all like-diamond phases in solid state.

Keywords: Semiconductor (AII-BVI, AIV, AIII-BV) phases, thermodynamic properties, entropy, Debye’s functions, similarity methode, critical assessment,

 

 

Biography:

Dr. Valery Vassiliev is a professor and researcher in the laboratory of chemical thermodynamics of the Chemical Department in Lomonosov University (Moscow).He has more 100 scientific publications, concerning thermodynamic properties and phase of diagrams of semiconductor system systems AII-BIV, AII-BVI, AIII-BV, AIII-BVI and metallic systems on the basis of rare earth metals. He is the author of review papers for the Handbook "Thermic constants of compounds", edited by academician V. P. Glushko, Edition VINITI (All-Union Institute of Scientific and Technical Information).

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