Studies of high performances 3D nanorods n-i-p diode oxygen sensor

In this study, a high performances Pd/WO₃/ i-amorphous carbon /p-Si/Al n-i-p Schottky diode with 3D nanorods structure was developed by DC bias-assisted hot-wire chemical vapor deposition (DB-HWCVD). All of the sensing layers were prepared by sputtering, except, the amorphous carbon film was deposited by a DB-HWCVD system. We used Raman, XRD, SEM and AFM, for bond structure measurement, analyzing crystalline, examination of surface roughness and morphology inspection, respectively. Based on the SEM images, we can see that at the etching temperature of 90°C and etching time of 60 minutes can get the best quality nanorods structure. To measure the voltage sensitivity of the device, current-voltage (I-V) curves were displayed on a curve tracer (HP 4145B). Experimental results show that, in 2D thin film structure, under 3000 ppm, the WO₃ sensor has the highest sensitivity of 199% (100°C) and 496% (400°C), respectively. Compared to the reported O₂ sensors, we achieved the higher sensitivity, lower operation temperature and wider sensing range.