Semiconductive Behavior of Polymer‐Derived SiCN Ceramics for Hydrogen Sensing

Abstract

A low-cost sensing mechanism of hydrogen gas is developed using polymer-derived ceramic, a liquid organic precursor, polysilazane with the addition of 5 wt% of photoinitiator, 2,2 Dimethoxy-2-phenyl acephenone. UV photopolymerization is utilized to partially cross-link the H-shaped free standing specimen, and then pyrolyzed at 1400°C in hot isostatic press under nitrogen gas to convert the partially cross-linked polymer into conducting and amorphous ceramic, silicon carbonitride. This work presents the preparation of free standing silicon carbonitride specimens as the sensor body for sensing hydrogen gas, depending on the semiconductive behavior of polymer-derived ceramics in high-temperature environments. The band gap of silicon carbonitride would be varied from adsorbing hydrogen molecules on the surface of the H-shaped free standing specimen with two different thicknesses. An amenable specimengeometry for the four-point test of measuring resistance is developed in a furnace filled with pure hydrogen and vacuumed environments.

SiCNO–GO composites with the negative temperature coefficient of resistance for high‐temperature sensor applications

“…Recently, polymer-derived ceramics (PDCs) have attracted great attention because of their corrosion resistances and high thermal stabilities. 1,2 The application of PDCs in hightemperature sensors, 3,4 lithium ion batteries, [5][6][7] and microelectromechanical systems [8][9][10] has been exploited. The electronic properties of PDCs have been suggested to depend on the concentration of nanosized carbon clusters (named "free carbon") in the PDCs.…”

Fabrication of dense polymer‐derived silicon carbonitride ceramic bulks by precursor infiltration and pyrolysis processes without losing piezoresistivity

“…Among the known PDCs, ternary silicon carbonitride (SiCN) ceramics received intensive studies in various aspects including their mechanical property, 11,12,19 thermal stability, 20,21 structural evolution, 22,23 oxidation, 24,25 creep behavior, 26 as well as electrical conductivity, [27][28][29] semiconductivity, 30,31 and piezoresistivity. 32,33 These properties make SiCN ceramics attractive for the fabrication of both structural and functional components that can bear loads and monitor variations in external factors such as temperature and stress.…”

Production of improved SiC and SiCN ceramics from polycarbosilane and polysilazane composites

“…SiC and SiCN ceramics are known for high thermal and oxidative stability as well as interesting mechanical and electrical properties. [1][2][3] SiC and SiCN ceramics can be readily synthesized by pyrolysis of carbosilane and silazane precursors under inert atmosphere, where the upper temperature of pyrolysis will have bearing on microscopic structure and material properties. [4] Liquid precursors of polymer derived ceramics (PDCs) are amenable to processing methods including injection molding, extrusion and film casting.…”