Positron Annihilation Study of Formation of Mg Vacancy in MgO
Positron Annihilation Study of Formation of Mg Vacancy in MgO
复制标题
DOI：
10.4028/www.scientific.net/msf.445-446.153
复制
发表时间：
2004-01
期刊：
影响因子：
--
通讯作者：
M. Mizuno;Y. Inoue;K. Sugita;H. Araki;Y. Shirai;T. Mizoguchi;I. Tanaka;H. Adachi
中科院分区：
文献类型：
--
作者：
M. Mizuno;Y. Inoue;K. Sugita;H. Araki;Y. Shirai;T. Mizoguchi;I. Tanaka;H. Adachi
采用正电子湮没测量和正电子寿命理论计算相结合的方法，研究了超稀三价杂质在MgO中诱导Mg空位的形成。未掺杂的MgO产生最短的正电子寿命为130 ps，比以前报道的使用单晶样品的166 ps短。掺杂样品的正电子寿命随Al或Ga掺杂浓度的增加而增加，并在170 ps左右达到饱和。这一结果表明，以前报道的值为166 ps归因于不散装，但由杂质引起的空位状态。采用半导体模型的理论计算与采用陷阱模型得到的130 ps的体寿命实验值吻合较好。计算的缺陷寿命比实验值长20 ps左右。这可能是由于Mg空位周围的晶格弛豫与正电子的捕获。
We have investigated the formation of Mg vacancy induced by ultra-dilute trivalent impurities in MgO by a combination of positron annihilation measurement and theoretical calculations of positron lifetimes. The undoped MgO yields the shortest positron lifetime of 130 ps that is shorter than that of 166 ps previously reported using a single crystal sample. The positron lifetime of the doped samples increases with the increase of the Al or Ga dopant concentration and is saturated at around 170 ps. This result indicates that the previously reported value of 166 ps is ascribed to not the bulk but the vacancy state induced by impurities. The experimental bulk lifetime of 130 ps, which is obtained by employing trapping model, is well reproduced by the theoretical calculation using the semiconductor model. The calculated defect lifetime is about 20 ps longer than the experimental value. This may be due to the lattice relaxation around Mg vacancy associated with the trapping of positrons.