title: Cobalt oxide nanosheet and CNT micro carbon monoxide sensor integrated with readout circuit on chip.
abstract: The study presents a micro carbon monoxide (CO) sensor integrated with a readout circuit-on-a-chip manufactured by the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process and a post-process. The sensing film of the sensor is a composite cobalt oxide nanosheet and carbon nanotube (CoOOH/CNT) film that is prepared by a precipitation-oxidation method. The structure of the CO sensor is composed of a polysilicon resistor and a sensing film. The sensor, which is of a resistive type, changes its resistance when the sensing film adsorbs or desorbs CO gas. The readout circuit is used to convert the sensor resistance into the voltage output. The post-processing of the sensor includes etching the sacrificial layers and coating the sensing film. The advantages of the sensor include room temperature operation, short response/recovery times and easy post-processing. Experimental results show that the sensitivity of the CO sensor is about 0.19 mV/ppm, and the response and recovery times are 23 s and 34 s for 200 ppm CO, respectively.
authors.affiliation: Department of Mechanical Engineering, National Chung Hsing University, Taichung, 402 Taiwan. cldai@dragon.nchu.edu.tw
authors.forename: Ching-Liang
authors.initials: CL
authors.lastname: Dai
authors.forename: Yen-Chi
authors.initials: YC
authors.lastname: Chen
authors.forename: Chyan-Chyi
authors.initials: CC
authors.lastname: Wu
authors.forename: Chin-Fu
authors.initials: CF
authors.lastname: Kuo
mesh_terms: D002248:Carbon Monoxide / Q000032:analysis*; D003035:Cobalt / Q000737:chemistry*; D004867:Equipment Design; D056656:Lab-On-A-Chip Devices; D046208:Microchip Analytical Procedures / Q000379:methods*; D049329:Nanostructures / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D012666:Semiconductors / Q000295:instrumentation
chemical_list: D037742:Nanotubes, Carbon; D010087:Oxides; D003035:Cobalt; D002248:Carbon Monoxide; C060728:cobalt oxide