Si中掺Er的原子构型与电子特性

采用定域密度泛函-离散变分方法(LDF-DVM)计算了Si中掺Er的原子构型与电子特性，并计算了O共掺杂对Si中掺Er体系的原子构型与电子特性的影响.结果表明，在没有O共掺杂时，Er处于四面体间隙位置时能量最低，此时Er的5d轨道在Si的导带中引入浅的共振态.处于替代位置的Er形成能略高，Er的5d轨道在Si的导带顶附近引入了受主态.当有O存在时，体系的形成能降低，能量最低的构型是Er处于六角形间隙位置，周围有6个O，此时Er的5d轨道在Si的导带下约为0.3eV处引入杂质态.从而解释了Si中掺Er体系在 关键词：

ATOMIC CONFIGURATION AND ELECTRONIC STRUCTURE OF ERBIUM-DOPED SILICON

The atomic configuration and electronic structure of erbium-doped silicon are studied theoretically by using local density formalism (LDF) and discrete variational method (DVM).The influence of codoping with oxygen is also investigated.The minimum-energy atomic configuration is that erbium occupies a tetrahedral interstitial site for an isolated erbium atom.In this configuration,Er 5d levels are located near the conduction band edge of Si in shallow resonance states. With the presence of oxygen,the binding energy of the structure decreases. In this case,the minimum-energy atomic configuration is that erbium occupies a hexagonal interstitial site with six nearest neighbors of oxygen atoms. An electronic state caused by the hybridization of Er 5d,O 2p and Si 2p electrons is located 0.3eV below the conduction band edge,which might be correlated with the deep level at E_c-0.15eV observed by the experimental measurement in Er and O codoped Si.