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Full-Text Articles in Physics
Atomic Size Mismatch Strain Induced Surface Reconstructions, Jessica E. Bickel, Normand A. Modine, Anton Van Der Ven, Joanna Mirecki Millunchick
Atomic Size Mismatch Strain Induced Surface Reconstructions, Jessica E. Bickel, Normand A. Modine, Anton Van Der Ven, Joanna Mirecki Millunchick
Physics Faculty Publications
The effects of lattice mismatch strain and atomic size mismatch strain on surface reconstructions are analyzed using density functional theory. These calculations demonstrate the importance of an explicit treatment of alloying when calculating the energies of alloyed surface reconstructions. Lattice mismatch strain has little impact on surface dimer ordering for the α2(2×4) reconstruction of GaAs alloyed with In. However, atomic size mismatch strain induces the surface In atoms to preferentially alternate position, which, in turn, induces an alternating configuration of the surface anion dimers. These results agree well with experimental data for α2(2×4) domains in InGaAs∕GaAs surfaces.
320-Channel Dual Phase Lock-In Optical Spectrometer, Petru S. Fodor, S. Rothenberger, J. Levy
320-Channel Dual Phase Lock-In Optical Spectrometer, Petru S. Fodor, S. Rothenberger, J. Levy
Physics Faculty Publications
The development of a multiple-channel lock-in optical spectrometer (LIOS) is presented, which enables parallel phase-sensitive detection at the output of an optical spectrometer. The light intensity from a spectrally broad source is modulated at the reference frequency, and focused into a high-resolution imaging spectrometer. The height at which the light enters the spectrometer is controlled by an acousto-optic deflector, and the height information is preserved at the output focal plane. A two-dimensional InGaAs focal plane array collects light that has been dispersed in wavelength along the horizontal direction, and in time along the vertical direction. The data is demodulated using …