(a) PL spectra of nanobelts obtained at temperature in pure dry air atmosphere (curve A), at concentration (curve B), and under vacuum conditions at temperature of (curve C). The data corresponding to curves A and B have been multiplied by a factor of 15 for better comparison. (b) PL intensity profile of curve C in log scale. The dashed lines represent the Gaussian best fit used to deconvolve the spectrum.
TRPL signal acquired in synthetic dry air for as-prepared sample of nanowires. The solid line represents a best fit of the data using a Kohlraush stretched-exponential decay function. Inset: Calculated distribution function of decay rates as a function of the decay rate constant (expressed in Hz).
(a) Normalized PL intensity vs concentration for nanowires as prepared (open circles) and after annealing in oxygen (solid circles). Solid line: Best-fit curve based on Langmuir function. (b) PL yield variations for as-prepared sample vs surface coverage .
Atomic structure of the oxygen-defective (101) surface investigated. The small balls represent the oxygen atoms and the positions of OVs.
Surface bands (solid lines) and projected bulk bands (shaded regions) for the (101) surface described by Fig. 4. Lines refer to occupied and empty bands. The zero of energy has been taken as the last occupied state energy.
Density of surface states of the stoichiometric surface (a) and of the (101) surface described by Fig. 4. The shaded regions represent the occupied states. The DOS is shown in units of number of states/eV per unit cell.
Computed JDOS for (a) stoichiometric (101) surface and for [(a) and (b)] oxygen deficient surface. Note that, for sake of clarity, the zero of curves (a)–(c) has been shifted. The main features in the JDOS have been labeled as P1–P5. The JDOS in (a) and (b) have been calculated as the sum over all the transitions among occupied to unoccupied states. In (c) the JDOS calculated for just the first valence to conduction band is reported. The energy gaps at the main BZ critical points have been explicitly shown with vertical arrows. A Gaussian broadening of has been used.
Geometrical parameters and gap energy of bulk (cassiterite) calculated with the present first-principles approach and comparison with available experimental data. The experimental data are taken from Ref. 1.
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