Abstract
We have measured the optical constants of from 0.62 to , using spectroscopic ellipsometry. The second derivatives of the dielectric function are examined through a critical point analysis, allowing us to inspect interband transitions from different points in space. The evolution of the band structure over a broad doping range is determined. Specifically, the critical point shifts to higher energies with increased doping of , while all other critical points appear unaffected. The evolution of the critical points results from the interplay between band-gap renormalization due to ionized impurities and hybridization of the induced impurity band with valence and conductions bands.
1 More- Received 13 April 2004
DOI:https://doi.org/10.1103/PhysRevB.70.205208
©2004 American Physical Society