ISSN:
1573-4854
Schlagwort(e):
porous materials
;
low-dimensional quantum structures
;
computer modeling
;
simulation
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
,
Maschinenbau
Notizen:
Abstract The detailed study of photoluminescence excitation (PLE) spectra in thick porous silicon (PS) layers is carried out using modified experimental technique. Instead of monochromatic detection usually used, a PLE signal is recorded over the whole emission band from a PS layer. For the first time, this technique allowed us to obtain the reliable PLE data up to far UV range of excitation energy Eexc = 5.4 eV. The PLE spectra showed increasing region below the maximum at Eexc ≈ 4.3 eV, then PLE intensity decreased monotonically. The absorption spectrum for PS layers is extracted from the same PLE data using depth profiling method. Low-energy region of the PLE spectra is satisfactorily simulated in terms of quantum confinement model assuming a constant quantum efficiency and log-normal size distribution of silicon nanocrystallites. The PLE decrease above Eexc ≈ 4.3 eV is discussed assuming that hot electrons may be injected from silicon crystallites to adjacent oxide phase in PS. In this way, leaving electrons give rise to nonradiative losses.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1023/A:1009615610867
