ISSN:
0392-6737
Keywords:
Optoelectronic devices
;
Other solid inorganic materials
;
Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter
;
Interfaces
;
heterostructures
;
nanostructures
;
Conference proceedings
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Summary We report the observation of strong red- and blue-light emission in free-standing porous-silicon samples prepared fromn + substrates at different anodization current densities. The surface morphology of the free-standing samples has been analyzed by means of atomic-force microscopy. Upon excitation with nanosecond pulses at room temperature, both blue and red luminescence bands appear, peaked around 3.2 and 2.0 eV, respectively. An extensive study of the time-resolved behavior of the photoluminescence signal reveals different dynamical features for the two spectral regions. The observed long decay time (several μs) of the red band reflects the predominant effect of non-radiative processes and is consistent with models based on excition diffusion through the interconnected silicon nanocrystals (quantum dots) skeleton. The relatively fast blue-band decay time (≈400 ns) is shown to be related to non-radiative recombination through trap states at the silicon nanocrystal surface.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02464692
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