Change in the Oxidation State of the Adsorbed Oxygen Equilibrated at 25°C on ZnO Surface during Room Temperature Annealing after Rapid Quenching
Change in the Oxidation State of the Adsorbed Oxygen Equilibrated at 25°C on ZnO Surface during Room Temperature Annealing after Rapid Quenching
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DOI：
10.1143/jjap.38.1534
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发表时间：
1999-03
影响因子：
1.5
通讯作者：
S. Fujitsu;K. Koumoto;H. Yanagida;Yuichi Watanabe;H. Kawazoe
中科院分区：
文献类型：
--
作者：
S. Fujitsu;K. Koumoto;H. Yanagida;Yuichi Watanabe;H. Kawazoe
在空气中从500°C淬火的多孔ZnO显示出非常低的电阻，具有非欧姆电流-电压行为。这是由于化学吸附氧形成的表面能垒所导致的。淬火试样的电阻和非欧姆指数随室温保温时间的延长而逐渐减小。电子自旋共振测量表明，化学吸附氧的氧化态从其高温型，O2-，到低温型，O2-和O-，而保持在室温下的变化。从该观点判断，电阻和非欧姆指数的降低是由于通过该氧化态的变化释放了被俘获的电子。掺杂CoO样品的电阻和非欧姆指数均高于未掺杂样品，且室温下的电阻和非欧姆指数的下降速度慢于未掺杂样品。氧化态的变化速率在CoO掺杂的样品中也较慢。
The porous ZnO quenched from 500°C in air showed very low electrical resistance with non-ohmic current–voltage behavior. This characteristic was resulted from the surface energy barrier formed by negatively charged chemisorbed oxygen. The resistance and the non-ohmic exponent of the quenched specimen gradually decreased by holding the specimen at room temperature. Electron spin resonance measurements showed a change in the oxidation state of chemisorbed oxygen from its high temperature type, O2-, into low temperature types, O2- and O- while being kept at room temperature. From this viewpoint, it was judged that the decrease in the resistance and the non-ohmic exponent resulted from the release of the trapped electron by this change in the oxidation state. The resistance and the non-ohmic exponent of the sample doped with CoO were higher than those of the undoped sample, and their decrease for the CoO-doped sample while being kept at room temperature was slower than those for the undoped sample. The rate of change in the oxidation state was also slower in the CoO doped sample.