Temperature effect, photoluminescence spectra

Fig. 4. (a) The photoluminescence spectrum of Ti-beta(OH) and the effects of the addition of C02 ((b) 0.5 mmol CO2/g) and H20 ((c) and (d) 0.1 and 0.5 mmol H20/g, respectively) molecules on the photoluminescence spectrum. Measurements were made at room temperature with excitation at 260 nm [Reproduced from Yamashita et al. (95) with kind permission of Kluwer Academic Publishers]. 

Fig. 12. Effect of the degassing temperature on the photoluminescence spectrum of powdered MgO. MgO degassed for 3 h rather than 2 h [reproduced with permission from Anpo el al. (9S)].

Figure 18.7 Effect of the addition of CH4 on the photoluminescence spectrum of V-MCM-41 (0.6 wt%) prepared by an acidic pathway, (a) After degassing at room temperature for 30 min.

Although we have demonstrated that Al-coated silicon is effective for the fabrication of oriented ZnO nanorods, one question is whether the presence of A1 introduces deep trap centers in the energy gap of ZnO. Figure 5.5e shows the room-temperature photoluminescence spectrum of the ZnO nanorods assembly. 

The demonstration in 1990 that porous silicon could emit efficient tunable visible photoluminescence (PL) at room temperature and attributed to quantum-size effects in crystalline silicon (Canham 1990) has induced considerable worldwide research activities in order to (i) identify the various PL bands and their respective properties and emission mechanisms, (ii) optimize the PL efficiency, (iii) optimize the PL stability, and (iv) tailor the PL spectrum (peak wavelength and FWHM). This chapter reviews briefly the specificities of porous silicon PL measurements, the PL of individual silicon nanocrystals from porous silicon, and the PL of porous silicon layers. 

As a potential material for photonic applications, it is important to evaluate the optical properties of ZnO. Photoluminescence measurement was performed on the ZnO nanorod/GaN substrate because it is an effective method to investigate the presence of defects. Figure 5.15 shows the PL spectrum at room temperature of the ZnO nanorods grown on GaN substrate (full line) and of the GaN substrate... 

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