Coupled Thermodynamic and Transport Analysis for a «Te+H2» System Used for Synthesis of Thread-Like Crystals of Tellurium
Восьмая Международная конференция «Кристаллофизика и деформационное поведение перспективных материалов»
05-08 Nov 2019
|| Kuzmin Andrey Olegovich
, Ismailov A M
, Rabadanov M R
, Shapiev I M
Boreskov Institute of Catalysis SB RAS
Dagestan State University
Tellurium is an elemental semiconductor, interest in which has recently increased due to the possibility of creating devices using structures based on thread-like crystals or whiskers (gas sensors, field-effect transistors, thermoelectric and piezoelectric devices, etc.) [1, 2].
Methods proposed for the growth of tellurium whiskers may be divided into two groups: (1) ‘wet’ chemical synthesis; (2) deposition from the gaseous phase. The thermal vacuum deposition technique is one of the most commonly used for producing thin films and thread-like crystals of tellurium. Its main disadvantage is that the vapor phase of tellurium is almost entirely composed of Te2 diatomic molecules, not Te atoms, leading to non-perfect surface structure (the mobility of Te2 atoms on the growing surface is low at substrate temperatures less than Тпл = 452C).
Thermochemical activation of the desired crystallization process of tellurium by introduction of H2 into the system is suggested, bringing H2Te molecule as a new precursor of growing crystals according to reaction Te + H2 = H2Te. This method allows to make tellurium crystals of different structural perfection and morphology: amorphous and epitaxial films, thread-like crystals (solid (Fig. 1b) and hollow-fiber (Fig 1a)), and microplates.
Coupled thermodynamic and transport analysis for the «Te+H2+H2Te» system is performed to describe the peculiarities of this approach.