Band Gap Engineering of Pb_1-xCd_xSe Thin Films Providing Mid-IR Photoluminescent-Based Light Emitting Diodes for Use in Nondispersive Infrared Gas Sensors

This work describes band-gap engineering of PbCdSe thin films for their use as light emitters in methane gas sensors. Pb _0.9 Cd _0.1 Se thin films were synthesized by pulsed direct current (DC) magnetron sputtering. Optical characterization of films demonstrated successful emission of light at 3.32 μm. Postsensitization (PS)—in highly reactive oxygen and iodine environment—was also analyzed. Design of experiments was used to optimize photoluminescence (PL) of PbCdSe films as a function of PS conditions. The studies demonstrated a high influence of PS temperature on PL properties. The thickness of the films was also demonstrated to have a significant effect on the enhancement of PL. The analysis of the morphology revealed that recrystallization of the material was key for the emission of light, probing its applicability as mid-IR light source in nondispersive IR gas sensors.