Bandgap energies, table

Table 3.1. Bandgap energy, Eg, and corresponding wavelength Abg (important for photo-excitation) of some semiconductors of electrochemical interest25. Zone of visible light (300—>950 nm)...

In view of the strong interest in very fast scintillator emission, it is not surprising that many other compounds have been investigated for cross luminescence. It is essential, of course, that the cross-luminescence emission energy is smaller than the bandgap energy, since otherwise the cross luminescence cannot be emitted (see also Fig. 3.27). This is illustrated in Table 9.9 [9]. The table shows excellent agreement between prediction and observation. 

TABLE 15.2 Bandgap Energies (Differences between Valence Band and Conduction Band) of Several Metal Oxides for Macroscopically Averaged Films... 

Semiconductors are materials that contain a relatively small number of current carriers compared to conductors such as metals. Intrinsic semiconductors are materials in which electrons can be excited across a forbidden zone (bandgap) so that there are carriers in both the valence (holes, p-type) and conduction (electrons, ra-type) bands. The crucial difference between a semiconductor and an insulator is the magnitude of the energy separation between the bands, called the bandgap (Eg). In the majority of useful semiconducting materials this is of the order of 1 eV some common semiconductors are listed in Table 1. 

Energy conversion table. Values of photon (vacuum) wavelength (nm), wavenumber (1 cm-1), frequency (THz) and energy (eV, J), as well as the energy per mole (J mol-1) of a chemical reaction can be easily converted if a ruler is placed horizontally over the chart. The bandgaps of different semiconductors are also indicated, as well as the wavelength of the intensity peak of a blackbody radiation for different temperatures. 

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