Photoluminescence infrared band

Photoluminescence Porous GaAs obtained in HCl exhibits visible region luminescence (around 540-570 and 850-870 nm) (Fig. 32). The green and infrared bands were interpreted by Schmuki and coworkers as being caused by a quantum confinement effect in GaAs microcrystaUites and nanocrystaUites, respectively [201, 207-209] whereas... 

In addition to the characteristic XRD patterns and photoluminescence, UV-visible and X-ray absorption spectra, another fingerprint thought to indicate lattice substitution of titanium sites was the vibrational band at 960 cm-1, which has been recorded by infrared and Raman spectroscopy (33,34). Although there is some controversy about the origin of this band, its presence is usually characteristic of a good TS-1 catalyst, although it turned out to be experimentally extremely difficult to establish quantitative correlations between the intensity of the 960 cm-1 band and the Ti content of a Ti silicate and/or its catalytic activity. 

The results of infrared absorption measurements on GaAstMn prepared by the solid-state diffusion method are also in good agreement with the A°(d5+h) center model (Linnarsson et al. 1997). According to infrared spectroscopy and photoluminescence (PL) measurements for GaAstMn with a Mn concentration of 1018 cm-3, this acceptor level is located 113 meV above the top of the valence band (Chapman and Hutchinson 1967 Ilegems et al. 1975). Two photoluminescence (PL) lines observed by Liu et al. (1995) in... 

Red and Near Infrared Photoluminescence Bands in Silica Nanostructures. 83... 

Figure 15-5. (a) Photoinduced absorption and photoluminescence (PL) spectra of MEH-PPV at 80 K (b, c) photoinduced absorption spectra of MEH-PPV/Ceo at 4K with argon ion laser at 514.5 nm modulated at 200 Hz. The abbreviations T, LE, HE, EA stand for triplet-triplet absorption, low-energy band, high-energy band, and electroabsorption features, respectively. IRAV stands for infrared activated modes (reproduced by permission of the American Physical Society from Ref. [19]). 

The photoluminescence of mesoporous silicon and silicon nanocrystals has received enormous study over the last 25 years. The spectroscopic nature and efficiency of various emission bands from the near-infrared to the ultraviolet are briefly reviewed, as are mechanistic studies on individual nanocrystals. Improvements in surface passivation and size control of sihcon nanocrystals have led to impressive photoluminescence quantum efficiencies in the visible range. 

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