Browsing by Subject "Green's functions"
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Item Chemical trends for deep levels associated with vacancy-impurity complexes in semiconductors(Texas Tech University, 1986-05) Shen, Yu-tangBeginning with the theory of deep traps due to vacancy-impurity pairs, we have developed a theory of deep levels associated with vacancy-impurity complexes in zincblende hosts. We consider triplet complexes which consist of a vacancy that is a nearest-neighbor to two identical, substitutional impurities. Such defects are thought to play an important role in recombination processes in device materials. On the basis of this theory, the chemical trends in such deep levels are predicted for 12 semiconductors and for the semiconductor alloy GaAsi-xPx* These predictions show that a triplet complex may have deep levels which are very different from those of either the isolated impurity or the vacancy-impurity pair. For example, complexing with a second impurity can produce deep levels at energies where neither the pair nor the isolated impurity produce any. Examples of such effects are discussed for GaP and GaAs1-xPx.Item Green's function methods in 1D nanoscale electron waveguides(2014-12) Corse, William Zachary; Reichl, Linda E.R-matrix theory has been used to analyze a variety of scattering potentials in ballistic electron waveguides. The S-matrix is the principal result of this method. Here we analyze ballistic electron scattering in a 1D waveguide with a step potential at its terminus using Green’s function theory. We calculate the S-matrix for this system, scattering particles’ quasibound states, and the survival probability of a particle initially localized in the step region. We then apply R-matrix theory to the same problem. In doing so, we demonstrate the versatility of the Green’s function approach, but also its relative complexity.