Determination of the dilation and vibrational contributions to the indirect energy band gap of diamond semiconductor

An empirical method is used to separate the indirect energy band gap vs. temperature curve of diamond semiconductor into its constituent lattice dilation and vibrational parts. The vibrational mechanism is described in terms of average frequencies over the acoustical and vibrational phonon bands. The results are found to be in agreement with the corresponding averages over the phonon density of states, which are also calculated. The pattern of behaviour exhibited by the group IV A semiconductors from this point of view is discussed.