Concept of Force Variation Due to Charged Defects in Elemental and Compound Semiconductors

Green's function calculations of force variation due to charged impurities in elemental and compound semiconductors are analysed on the basis of simple physical arguments. It is strongly suggested that the trends of force variation may not be related with the long range Coulomb interactions, however, the important criteria should be the effect of electric field of charged impurity on its nearest neighbour bonds that mainly affects the short range couplings. Some new experimental results by i.r. method due to Si and Cl impurities in CdTe are also included that lend additional justification to the arguments.