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Effects of pressure on the optical absorption and photoluminescence of Wöhler siloxene

1994; American Physical Society; Volume: 49; Issue: 8 Linguagem: Inglês

10.1103/physrevb.49.5362

1095-3795

Stefan Ernst, M. Rosenbauer, Ulrich T. Schwarz, Péter Deák, K. Syassen, M. Stutzmann, M. Cardona,

Molecular Junctions and Nanostructures

We have investigated the effect of hydrostatic pressure (P\ensuremath{\le}5 GPa) on optical absorption and photoluminescence spectra of W\"ohler siloxene (${\mathrm{Si}}_{6}$${\mathrm{O}}_{3}$${\mathrm{H}}_{6}$, as prepared) at T=300 K. The absorption edge energy near 2.75 eV decreases linearly with pressure at a rate of -30\ifmmode\pm\else\textpm\fi{}3 meV/GPa. For the position of the maximum of the green luminescence band we find a similar pressure coefficient (dE/dP=-24\ifmmode\pm\else\textpm\fi{}3 meV/GPa). The intensity of the green luminescence shows a reversible decrease with increasing pressure. The pressure dependence of interlayer and intralayer lattice constants has been determined by x-ray powder diffraction. The observed changes in optical transition energies are discussed in the framework of a semiempirical quantum-chemical calculation of the electronic structure of siloxene.