Effect of Thermal Initiator Concentration on the Electrical Behavior of Polymer‐Derived Amorphous Silicon Carbonitrides

Abstract

The electric conductivity of polymer-derived silicon carbonitrides made from a polysilazane modified with different amounts of thermal initiator is measured at room temperature. It is found that the thermal initiator has a significant effect on the electric conductivity, which first increases and then decreases with increasing thermal initiator concentration. The highly conductive sample exhibits a very high piezoresistive coefficient and weak temperature dependence as compared with the low conductive samples. The microstructures of the materials are characterized using a Raman spectroscope. Based on these results, two conducting mechanisms are identified: the highly conductive sample is dominated by the tunneling-percolation mechanism, while the low conductive samples are dominated by matrix phases. The effect of the thermal initiator on the development of the microstructures of the materials is discussed.

Tris(diethylamino)silane—A new precursor compound for obtaining layers of silicon carbonitride

“…These free carbon clusters play an important role in the for mation of properties of the silicon carbonitride layers. For example, the conductivity of these layers strongly depends on the concentration of carbon clusters [59], and the high temperature thermal stability is also related to the presence of free carbon [60]. Unfortu nately, while the presence of free carbon is observed often, it is impossible to determine its amount.…”

Semiconductor‐conductor transition of pristine polymer‐derived ceramics SiC pyrolyzed at temperature range from 1200°C to 1800°C

“…The parameters determined by curve fitting are summarized in Table . The low energy difference between the mobility edge ( E C ) and the Fermi level ( E F ) suggests that with increased pyrolysis temperature, the density of the defect states has increased which brings the Fermi level closer to the mobility edge …”

“…As the properties and structures of polymer‐derived ceramic (PDC) depend on materials composition and synthesis conditions and therefore, it would be possible to tailor them for specific applications . This is particularly evident for the unique structure composed of a silicon tetrahedron containing the amorphous phase and the highly disordered carbon, which makes the electrical properties of polymer‐derived ceramic silicon carbide (PDC SiC) tailorable …”

HTGR Measurements and Instrumentation Systems

“…The sensor body is deformed by the difference between the internal and external pressure and the electrical resistance; the sensor body is dependent on its strain state. 47 A unique characteristic of polymerderived ceramics is their formability prior to firing, allowing creation of complex shapes with designed pore structures. 48 Polymer-derived ceramic bodies based on these principles are already under development as high-temperature, high-pressure sensor materials focused on power generation.…”