Cu掺杂SnO_2纳米粉体的制备及气敏特性

Preparation and Gas Sensing Characteristic of Cu-Doped SnO_2 Nano-powders

控制不同n（Cu^2＋）／n（Sn^4＋），用均匀共沉淀法制备了平均粒径约80nm的金红石型结构Cu掺杂SnO2纳米粉体；并以白云母为基片制备出Cu掺杂SnO2气敏元件。用TG—DSC、XRD、SEM对样品的相变、结构、形貌进行了分析，并测试了气敏元件的阻温特性和75℃氢气敏感性能。结果表明，Cu掺杂抑制了SnO2晶核的生长，使SnO2结晶度由约75％减小到50％，晶粒尺寸由约18nm减小到6nm；Cu掺杂使n型半导体SnO2的空气电阻值由1～8kΩ提高到9×10^5～3×10^7MΩ，并使元件在75℃对体积分数为2000×10^-6氢气的灵敏度提高约20倍；n（Cu^2＋）／n（Sn^4＋）≈0．01时，元件对体积分数为4000×10^-6氢气的灵敏度高达约42。

Cu-doped SnO2 nano-powders were prepared by homogenous co-precipitation method with different n （ Cu^2＋ ）/n （ Sn^4＋ ）. The ruffle type Cu-doped SnO2 grains were about 80 nm. The phase transformation, structure and shape of samples were analyzed according to TG - DSC, XRD and SEM. The resistance-temperature characters and sensitivities in H2 atmosphere at 75 ℃ of the sensors were tested. As a result, doping of Cu^2＋ restrains the growth of grains. The crystalline degree of SnO2 decreases from about 75% to 50% and the crystal size of SnO2 decreases form about 18 nm to 6 nm. In addition, doping of Cu^2＋ increases the resistance of n-type SnO2 from 1 - 8 kΩ to 9×10^5 - 3×10^7 MΩ in the air atmosphere and improves the sensitivities of sensors by about 20 times for 2 000×10^-6 H2 at 75 ℃. The sensitivity of sensors for 4 000×10^-6 H2 was as good as 42 when n（Cu^2＋ ）/n（Sn^4＋ ） was about 0.01.