Ultra-sensitive NO_2 sensor based on vertically aligned SnO_2 nanorods deposited by DC reactive magnetron sputtering with glancing angle deposition technique

摘要

Highly responsive NO_2 gas sensors at low operating temperature based on tin dioxide (SnO_2) nanorods were successfully developed by DC reactive magnetron sputtering with the glancing angle deposition technique. Characterization results by grazing incident X-ray diffraction (GIXRD) and field-emission scanning electron microscopy (FE-SEM) showed that the as-deposited and annealed SnO_2 nanorod structures exhibited rutile phase and crystallinity was improved after annealing at 300 and 400 ℃. The gas-sensing results indicated that nanorod structure and annealing treatment provide significant improvement on NO_2 response and selectivity against H_2, H_2S, ethanol and CO. As a result, 400 ℃-annealed SnO_2 nanorods exhibited a very high NO_2 response of 5310 to 5 ppm NO_2 at the optimal operating temperature of 150 ℃. Thus, SnO_2 nanorod prepared by sputtering with GLAD is a promising candidate for ultra sensitive and selective NO_2 detection.