The optical glow of ceramics that becomes established during the constant state of flash, known as Stage III in flash sintering experiments, is investigated. The specimen temperature in this state is obtained from in-situ experiments at the Pohang Light Source II. The measurements of the specimen temperature agree very well with the predictions from the black body radiation model. The optical emission spectrum from the specimen is measured from the visible into the deep infrared, and compared with black body radiation that would have been expected from Joule heating. It is concluded that the specimens radiate by electroluminescence, which is ascribed to electron-hole recombination of excitons. The phenomenon is likely the same as discovered by Nernst at the turn of the twentieth century.

A flash sintering experiment can be carried out by applying an electric field and heating the specimen at a constant rate. The flash event occurs at a specific temperature that depends on the strength of the electric field. Alternatively, the furnace can be held at a constant temperature and the voltage applied as a step function; after an incubation time there is a highly non-linear rise in conductivity. This incubation step is called Stage I. The non-linearity is constrained by switching the power supply to current control. This short transient, during which the sample sinters nearly instantaneously, is the second stage. Under current-control, the (essentially dense) sample remains in a highly excited state indefinitely, which we call Stage III. In this state, the samples are often brightly electroluminescent emitting a green glow; unusual phase transformations occur and the rate of chemical reactions is greatly enhanced. We infer that these manifestations are evidence of a defect catastrophe that includes unusual generation of electrons, holes and point defects, which can produce sintering, electronic conductivity, electroluminescence, and phase transformations, all at the same time. We hypothesize that both Joule heating and electric field are necessary for this catastrophe.

Titanium alkoxide films known as "titanicones" were grown using molecular layer deposition (MLD) techniques using the sequential exposure of TiCl 4 and glycerol. These titanicone MLD films were then pyrolyzed under argon to yield conducting TiO 2 /carbon composite films. The Raman spectra of the pyrolyzed titanicone films revealed the characteristic "D" and "G" peaks associated with sp 2 -graphitic carbon. X-ray diffraction analysis of the pyrolyzed titanicone films displayed the signatures for anatase and rutile TiO 2 after heating to 600 °C and then only rutile TiO 2 after heating to 900 °C. X-ray photoelectron depth profiling of the pyrolyzed titanicone films showed that the carbon was distributed throughout the film and began to segregate to the surface after heating to 900 °C. The sheet resistance of the pyrolyzed titanicone films dropped dramatically versus pyrolysis temperature and reached a minimum sheet resistance of 2.2 × 10 4 Ω/□ after heating to 800 °C. On the basis of the measured film thickness of 88 nm, the resistivity of the pyrolyzed titanicone film after heating to 800 °C was ρ = 0.19 Ω cm. Segregation of other hybrid organic− inorganic films into sp 2 -graphitic carbon and metal oxide domains after pyrolysis under argon was also observed for alucone films and various metalcone films based on Zn, Zr, Hf, and Mn. The conducting TiO 2 /carbon composite films and other metal oxide/ carbon composite films could have important electrochemical applications as electrodes for Li ion batteries or pseudocapacitance supercapacitors.

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