We have developed 4.26 μm room temperature resonant-cavity light-emitting diodes (RCLED) using III-V material
system (InAs, InSb, and GaSb). The emission spectrum of RCLED closely matches the CO2 absorption profile. The
wavelength of the peak of the emission spectrum is stable with respect to wide variations in the temperature and the drive
current. Consequently we were able to develop a low cost RCLED based CO2 sensor operating over a wide temperature
ranges of +5 to + 45 degrees C and minus 20 to + 60 degrees C (depending on the IR detector used) without a TE-cooler.
These sensor devices consume very low power, at the level of mW, with a fast response time of 10 sec and better. It can
measure CO2 levels in the range 0-10,000ppm with an accuracy of better than +-5%.