Si中深能级T2对称波函数理论

木文在文献5,6]所发展的在位缺陷势格林函数方法基础上,进一步讨论Si中短程缺陷势引入的T₂对称深能级波函数性质。第一次给出了Si禁带中部很宽能量范围之内T_2对称波函数的完整数据。波函数在缺陷最近邻四个格点的占据几率P₁有一高达50％以上峰值。该部分相当于四个最近邻格点指向缺陷的杂化轨道准悬键的T₂组合。第0,1,2三个格点壳层波函数占据几率之和约为70％。波函数其余部分较平缓地分布在一相当大空间。波函数的以上特征与禁带中部能量位置关系不灵敏。但在靠近导带E_c和满带E_v的浅能量区,以上P₁峰趋于消失,整个波函数在空间的分布趋于平坦。Si空位在禁带引入一个T₂对称深能级,位于E_v以上0.51eV处。 关键词：

THEORY OF T2 SYMMETRIC DEEP LEVEL WAVE FUNCTIONS IN Si

A systematic investigation and numerical results of calculation of T₂ symmetric deep level wave function induced by short range defect potential in Si are described, based on a recently developement on site defect potential Green's function method. 5,6] Such a complete information of T₂ symmetric wave functions in Si is presented for the first time. The occupation probability P₁ of the wave function located around four nearest neighbour sites of the defect center has a peak exceeding 50%. This part of wave function could be described by T₂ symmetric combination of four hybrid orbital quasi dangling bonds located at four nearest neighbour sites and pointing toward the defect center. The total occupation probability of wave function located on the 0,1,2 shells arround the defect center is about 70%. The rest part of the wave function extends diversely over a wide range of space. The characteristics of the wave function are insensitive to the defect energy over most part of the energy range in the gap. Only when the defect energy level approaches very closely to the band edge of either conduction (E_c) or valence (E_v) band, the aforementioned peak P₁ disappears and the wave function extends smoothly all over the space. A T₂ symmetric deep level due to ideal vacancy is found at 0.51 eV up to the E_v.