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EXPERIMENTAL STUDY ON NUMBER DENSITY AND MOBILITY OF ELECTRIC CARRIER IN A CERAMIC INSULATOR,ALUMINA

陶瓷绝缘体氧化铝中载流子数密度和迁移率的实验研究

基本信息

批准号：
06650737
负责人：
SHIKAMA Tatsuo
金额：
$ 1.22万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650737/
关键词：
CERAMICS INSULATOR ELECTRICAL CONDUCTIVITY ELECTRIC CARRIER MOBILITY NUMBER DENSITY アルミナ照射誘起伝導

项目摘要

It has been attempted to measure a number density and a mobility of an electric carrier in a ceramic insulator, alumina. The specimens used are highly pure alumina polycrystals and a highly pure single crystal sapphire. Electrons are thought to be responsible for the electric conductivity in alumina and sapphire. However, the electrical conductivity in these materials are very low, namely in the order of 10^<-13>Sm^<-1>, at moderate temperatures. Thus, the measurements of the electrical conductivity as well as the number density and the mobility of the electric carrier is very difficult in general. In this experiment, we tried to use the phenomenon so-called radiation induced condutivity (RIC) to increase the electrical conductivity, thus, increasing the number density of the carrier. The RIC is the phenomenon similar to the phtoconductivity in semiconductors. It is in general very difficult to measure the electrical conductivity in radiation environments, but by refining a techniques it became possible to measure the electrical conductivity reliable in the radiation environments in this experimental study. The developed technique made it possible to measure the electrical conductivity in the range of to 10^<-11>-10^<-4>S.Using this technique, we obtained the data concerning dependence of the electrical conductivity on the crystal orientation, microstructures of the crystals, and so on. Also, we observed some non-ohmic behavior in insulators under irradiation. This non-ohmic behavior may be caused by the charge-ups of electric carriers near the boundaries between the electrodes and the insulators or at grain boundaries. Also, some charge trap effects at some point electrical impurities may be responsible. The obtained data will give us the quantitative information concerning the number density and the mobility of the electrical carrier in alumina and sapphire.

它已被尝试测量数字密度和电流子的迁移率在陶瓷绝缘体，氧化铝。所用的样品是高纯度的氧化铝多晶和高纯度的蓝宝石单晶。电子被认为是氧化铝和蓝宝石导电的原因。然而，在中等温度下，这些材料的电导率非常低，即在10^<-13>Sm^<-1>的数量级。因此，电导率以及电载流子的数量密度和迁移率的测量通常是非常困难的。在本实验中，我们尝试使用所谓的辐射诱导导电性（RIC）现象来增加电导率，从而增加载流子的数量密度。RIC是一种类似于半导体中的光导现象。一般来说，在辐射环境中测量电导率是非常困难的，但通过改进技术，在本实验研究中可以可靠地测量辐射环境中的电导率。所开发的技术使测量电导率在10^<-11>-10^<-4>S范围内成为可能。利用该技术，我们获得了电导率与晶体取向、晶体微观结构等关系的数据。此外，我们还观察到绝缘体在辐照下的一些非欧姆行为。这种非欧姆行为可能是由电极和绝缘体边界附近或晶界处的载流子的充电引起的。此外，某些电荷陷阱效应在某些电杂质可能负责。所获得的数据将给我们提供有关氧化铝和蓝宝石中载流子的数量密度和迁移率的定量信息。