Determination of the dilation and vibrational contributions to the temperature shift of excitons in CdS: melting of semiconductors

Abstract

An empirical method was used to separate the temperature shift curves of the A- and B-exciton energies in CdS. It was found that the lattice dilation contributed an amount −2.3 × 10−5 eV/K to the temperature shift, and the frequencies of the terms representing the electron–phonon interaction were found to correspond to the average frequencies of the phonons in CdS. The data on the semiconductors analyzed up to now by the empirical method (C, Si, Ge, CdS) were examined at the melting point temperatures of the materials and it was found that the combined results could be described by simple equations. It was found that the r.m.s. vibrational amplitude of the atoms in the above four materials was nearly identical at their melting temperatures.