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

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 λ 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 λ can be related to the average energy gap Eh arised from the symmetric potential Vcov, the energy gap C arised from the anti-symmetric potential Vion and the total energy gap Eg, hence, the dependence of λ on the fraction of the spectrum ionicity fi and the ratio C/Eh are deduced. From the dependence of λ 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 γ and the piezoelectric constant epol 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, γ and epol on fi 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.