ZnO半导体粉体制备工艺与电阻率的关系

Relationship Between Preparation Process and Resistivity of ZnO Semiconductor Powder

采用固相合成法制备了氧化铝掺杂的氧化锌半导体粉体,通过X-射线衍射分析,探讨了掺杂量、煅烧温度和保温时间对粉体导电性能的影响.实验发现:Al2O3的掺杂量高于0.5%(摩尔比)时,会生成ZnAl2O4尖晶石相,降低ZnO的电导率;在一定的温度和保温时间下,才能保证有足够的Al3+进入ZnO的晶格,从而获得电阻率比较低的ZnO半导体粉体;温度过高和保温时间过长都会导致Al2O3与ZnO反应生成尖晶石,减少Al3+对Zn2+的置换率,并对电子产生散射,从而导致ZnO半导体粉体的电阻率升高;当Al2O3掺杂量为ZnO的0.5%(摩尔比)时,在1300℃下保温3h所得到的ZnO粉体的电阻率为18kΩ.cm.

ZnO semiconductor powders doped with Al2O3 were synthesized via solid synthesis. The influences of Al2O3 doping content, calcination temperature and soaking time on the resistivity of ZnO powders were then analyzed by means of XRD. Experimental results show that ZnAl2O4 spinel may exist in ZnO semiconductor powders and the electric conductivity may decrease when the doping content of Al2O3 overruns 0. 5% in molar ratio, and that ZnO powders with low resistivity can be obtained when enough Al^3＋ enter the ZnO crystal lattice at a certain calcinations temperature for a certain soaking time. However, excessive calcination temperature and soaking time may result in the formation of ZnAl2O4 spinel from Al2O3 and ZnO, which makes the replacing ratio of Al^3＋ for Zn^2＋ decrease and the electron scattering occur, thus increasing the resistivity of ZnO powders. It is also indicated that the synthesized ZnO powders are of a resistivity of 18 kΩ· cm when the reaction system is calcined at 1300℃ for 3 h with a Al2O3 doping content of 0. 5%.