Fundamental Investigations of Amorphous Semiconductors and Transition Metal Oxides.
Abstract
The density of states for amorphous Ge and Si has been obtained for the top 5 eV of the valence band and bottom 10 eV of the conduction band. These results have been confirmed by other measurements. This work has produced experimental evidence that the band edges in properly prepared amorphous Ge and Si are much sharper and the density of states in the band gap can be much lower than previously believed. Theoretical arguments have appeared which support these results. Criteria were developed for obtaining sharp band edges and minimizing the density of states in the bandgap. The result that band edges can be sharp in amorphous materials and that the density of states in the bandgap region can be reasonably low have great importance for the design and fabrication of amorphous devices. Experiments have been carried out with large amounts of As impurity in Ge. The results from ultraviolet photoemission studies on SrTiO3, TiO2 and VO2 are summarized in terms of the electronic structure of these materials. VO2 has been studied in both the metallic and semiconducting forms. Results have been obtained from a UV polarizer especially designed and constructed on this project. (Modified author abstract)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 15, 1974
- Accession Number
- AD0774298
Entities
People
- William E. Spicer
Organizations
- Stanford University