High performance room temperature GaN-nanowires hydrogen gas sensor fabricated by chemical vapor deposition (CVD) technique

Pt-decorated GaN nanowires with significant improvement in H 2 gas-sensing performance at room temperature

“…The gas-sensing properties of the sensor based on 1-D According to previous our research work [63,64], it has been reported that sensor fabricated from uncoated GaN NWs shows much lower response to H 2 gas at various operating temperatures than our present work. Therefore, it can be easily noticed that coating with Pt improves drastically the response of the sensor and results in lowering its operating temperature, at which the sensor response is maximized.…”

“…When the dimension of nanomaterial are diminishing, the relaxation of q = 0 selection rule owing to the influence of finite size for nanostructured materials forms new phonon modes to generate modes that match to q ≠ 0 phonons. The three peaks appearing around 250, 315 and 420 cm -1 could be possibly attributed to the zone-boundary phonon, activated by crystalline defects and finite size effects, as well as the acoustic overtone of crystalline wurtzite GaN [61][62][63][64].…”

“…, O − ) and H 2 gas molecules[13,50,63,64].The basic parameters limiting gas sensing characteristics of 1-D semiconducting nanostructures are mainly the surface-to-volume ratio and surface morphology[16,18,20,25,[55][56][57][58][59][60][61][62][63][64][65][66][67]. 1-D NWs usually have rough and zigzagged surface.…”

“…The sensing mechanism at GaN NWs surface can be clarified in terms of oxidizing/reducing gas effects[20]. It is well-reported that NWs surface adsorbs oxygen species(O -2,O 2-, O -) from air by capturing conductive electrons from the conduction band of GaN and makes the NWs further resistive[63,64,66,68]. Furthermore, GaN NWs with a high surface-to-volume ratio offer a huge number of atoms (or molecules) existing at the surface that can contribute in surface reactions.…”

Temperature balanced hydrogen sensor system with coupled palladium nanowires

“…Up to now, various one-dimensional structures like ZnO, GaN, and core-shell nanorods have been synthesized by different methods using a bottom-up fabrication technique, and then used to further build up ultrasensitive hydrogen sensors operating at room temperature [5][6][7][8]. Although these bottom-up synthesized hydrogen sensing devices are reported to have excellent sensitivity properties towards hydrogen, they may have a cross sensitivity towards other gases like e.g.…”