Optical Absorption due to Free Holes in Germanium: A Comparison of Theory and Experiment

Abstract

The absorption due to direct inter-valence-band transitions of free holes in germanium has been investigated. A comparison is made between the computed and experimental change of absorption induced by a small increment of lattice temperature. The theory is based on the exact treatment of the k·p interaction between bands, and is extended here to include evaluation of the optical matrix elements. A method of computing the absorption is described ln which the full complexity of the band structure is incorporated. The results of the calculation are fitted to the experimental data by varying the parameters within the limits provided by known band-structure data. A good fit is obtained, but discrepancies exist which are outside experimental error.