摘要
采用定域密度泛函离散变分方法（ＬＤＦＤＶＭ）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体系在有Ｏ和没有Ｏ共掺杂时原子构型的变化，以及Ｏ的存在可以提高Ｅｒ在Ｓｉ中的固溶度等实验现象，并初步解释了深能级瞬态谱对Ｅｒ和Ｏ共掺杂Ｓｉ体系测量的实验结果．
Abstract 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 0.3 eV 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.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
1998年第4期652-657,共6页
Acta Physica Sinica
基金
国家自然科学基金
