The presence of configuration interaction, between the "internal" acceptor states of group III impurities in silicon and P₃⁄₂ band Bloch states, has been observed. The effect of impurity-impurity interaction on the line shape of the boron, gallium and indium internal acceptor lines has been studied. The observed characteristic asymmetric line shape is explained by introducing the interaction of the internal state with the degenerate P₃⁄₂ valence band Bloch states, and the inhomogeneous impurity-impurity interaction. The ionization energy of the substitutional impurity in the host lattice is found to be a deciding factor in this interaction.
The internal and external absorption spectra of silicon doubly-doped with boron and indium acceptors is studied. The observed broadening of the boron external absorption lines in Si(B,In) is explained by neutral impurity scattering. The presence of indium in Si(B,In) crystal lattice, modifies the P₃⁄₂ valence band Bloch states and hence the configuration interaction. This modification is found responsible for the observed features of the boron 2p′ internal line in Si(B,In).
The coupling between the lattice and the impurity bound carrier for deep monovalent acceptors in silicon, such as gallium and indium, is found to be stronger than for the shallow boron impurity. This suggests the possible existence of phonon-assisted transitions associated with these deep impurities. Such transitions are observed in the absorption spectrum of indium doped silicon. The phonon-assisted transitions are superimposed on the photoionization continuum transitions of the indium acceptors. Interference effects between the phonon-assisted transition and the transitions to the continuum states modify the position and line shape of the transitions. Using the phonon dispersion curves for silicon, interpretation of the results is presented.
As a supplementary study, the temperature dependence of the indium external line 2, is investigated. The temperature dependence of halfwidth of indium line 2 in Si(In) supports the stronger electron-phonon coupling in Si(In). / Science, Faculty of / Physics and Astronomy, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/34607 |
| Date | January 1970 |
| Creators | Bhatia, Krishan Lal |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
Page generated in 0.001 seconds