Carbon monoxide sensing at room temperature via electron donation in boron doped diamond films

We report room temperature detection of carbon monoxide (CO) below 100 parts per million in air using boron doped diamond films prepared by hot filament chemical vapor deposition method. Gas sensing characteristics are observed to be improved with larger grain size in the films. Sensing characteristics for 100 ppm CO with response time of 30 s and recovery times of ∼50 s at room temperature show the excellence of boron doped diamond as CO sensor material. The lowest values of response time ∼5 s and recovery time ∼20 s were observed for BDD with grain size of 1 μm for 1000 ppm of CO in air. The carbon monoxide sensing mechanism is attributed to electron donation to p-type boron doped diamond as a result of CO oxidation on its surface.