Isa Anshori
Carbon Monoxide (CO) or called as “silent killer” is a odorless, colorless, and tasteless gas. CO binds to hemoglobin form to carboxyhemoglobin (COHb). CO bound to Hb is incapable to carry oxygen (O2). Hb has a 210 times greater affinity for carbon monoxide than oxygen, which explains the extraordinary toxicity of CO even when its concentration in inspired air is relatively low. 0.02% CO which is inhaled for 2 hours can cause symptoms, such as headaches and nausea. A concentration of 0.1% results in a loss within 1 hour and death due to asphyxia in only 4 hours. In order to prevent any fatal accident due to the hazardous CO gas exposure, many gas sensors were developed from various metal oxides. ZnO is one of metal oxides believed to react with oxygen around and adsorb O- (100-300°C), O2- (below 100°C), and O2- (over 300°C) into semiconductor surface. ZnO, as an n-type semiconductor, has the unique characteristics needed for ideal gas sensors such as 3.37 eV wide band gap, 60 meV large exciton binding energy, high electron mobility, photoelectric response, good chemistry and thermal stability.
Penerapan Karya Tulis
CO gas exposure.