The output from a ruby laser was homogenized, and used to laser anneal the active layer of GaA1As double heterostructure wafers in an attempt to improve the radiative efficiency of the active layer. At anneal energies exceeding the estimated threshold for melting of the active layer, the radiative efficiency was reduced by a factor of two. Subsequently, semiconductor laser diodes fabricated from laser annealed heterostructures performed much worse than those fabricated from unannealed heterostructures. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The problem of this study was the measurement of the proton-proton separation in the water molecule of hydration in a single crystal of potassium oxalate monohydrate.

No description available.

No description available.

Note:

No description available.

No description available.

No description available.

In part (a) of the abstract, the decimal points should be subscript. / An algebraic procedure for considering the general n-tuple problem for a random defect lattice is developed in this thesis. When specialized to pairs {n=2) the deviations from randomicity have also been considered. The low concentration defect theory (n=l) is used to calculate: a) the frequencies and widths of phonons in disordered Cu₀.₉₇ Au₀.₃₃ b) the frequency shift of singular points in the defect-induced (Na⁺ , Sm⁺⁺) far infrared spectrum of RBr as a function of defect concentration c) the one phouon side bands of H₂, D₂, and N₂ in solid Ar. In order to take into account the "long range" behaviour of random substitutional defects, an effective lattice theory is formulated. This theory proves essential to the discussion of the Cu/Au dispersion curves and the one phonon side band of the vibrational spectrum of a H₂, (D₂) molecule in solid Ar. / Thesis / Doctor of Philosophy (PhD)

A "liquid crystal" is a substance whose properties are intermediate between those of a crystalline solid and an isotropic liquid. The molecules within a liquid crystal are partially ordered, but they are able to translate easily in at least one direction.