化合物半导体中离子射程参数与化学键中离子特性间关系研究

INVESTIGATION ON THE IONIC CHARACTERISTIC OF CHEMICAL BOND IN COMPOUND SEMICONDUCTOR AND THE EFFECT OF IT ON THE IONIC RANGE PARAMETERS

本文基于分子轨道法线性组合理论,推导出不同原子组成的分子的久期方程,从而得出分子波函数线性组合的特征常数N和λ的定量关系式,以及成键合能量和反键合能量的方程式.并通过这两能量之差,使N,λ系数与晶体对称势V共价所产生的平均能隙Eb,反对称蛰V离子所产生的能隙C和其总能隙Eg等相联系起来,导出了λ与分数光谱离子性fi和C/Ek比值间的关系式.由λ,N 可导出fi与化合物半导体中离子射程参数间的关系式. 应用上述一些关系式结合闪锌矿和纤锌矿结构特性,可以很好地解释两种结构的偏离系数γ(即化合物半导体中实际电子阻止本领对Bragg电子阻止本领的偏离系数)间互成倒数和压电系数e_(pol)的符号相反的原因.因此从C/Eh,γ,e_(pol),对fi三曲线转折点完全一致,可以清晰地看出半导体化合物的价键和晶体结构特性决定了它的一系列物理、化学特性.

Based on the molecular-orbital theory, the secular equation of molecule consisted of two different atoms can be deduced. Solving the above equation, the quantitative expression of the characteristic constant N and A for the linearly combined wave function of the compound and the equation of the bond forming energy or the anti-bond forming energy are obtained. Using the difference between this two energies, the N and A can be related to the average energy gap Eh arised from the symmetric potential V(cov), the energy gap C arised from the anti-symmetric potential V(ion) and the total energy gap Eg, hence, the dependence of γ on the fraction of the spectrum ionicity fi and the ratio C/Eh are deduced. From the dependence of γ on fi, the expression connecting fi and the deviation coefficient γ for the electronic stopping power of the compound may be obtained. According to the above equations and considering the structural characteristic of zincblen-de and wartzite structure, the reason which causes the difference of the deviation coefficient Y and the piezoelectric constant e(pol) between the two structures can be well explained. The same turning point can be found in all the three curves expressing the dependence of C/Eh, y and e(pol) on f1 respectively, hence, we could see that the bond and structural property of crystal will be the most essential cause which results in the change of chemical and physical property of semiconductor compound.