High Temperature Coupling of IR Inactive C=C Mode in Complementary Metal Oxide Semiconductor Metamaterial Structure

High temperature (up to 400 degrees C) coupling of infrared (IR) inactive >C=C< mode is reported in complementary metal oxide semiconductor (CMOS)-compatible refractory metamaterial filter and absorber structure by leveraging the carbon defects in tetraethyl orthosilicate obtained plasma enhanced chemical vapor deposition SiO2 thin film. Here, the role of strain gradient induced dipole moment in high stress configuration on the activation of otherwise inactive >C=C< vibration at IR is confirmed. The unusual suppression of the transition is also observed in the absorber structure when the cavity mode strongly overlaps with it. Finally, 14 times better modulation of resonance spectrum is reported by such coupling in absorber configuration that supports thin film interference. The numerical and analytical study of the effect is found to be qualitatively in agreement with the experimental results. The study can set new paths toward more efficient design of spectrally selective thermophotovoltaic energy emitter at mid-IR and novel mechanism for high temperature sensing on the ubiquitous CMOS platform.