Luminescence spectra doping effects

We believe that the luminescence at 1.0 eV is due to a structural damage induced by ion implantation rather than to a chemical doping effect, since the spectrum does not depend on the chemical species of the ion. These centers may be similar to the vacancies induced by 3-MeV electron-beam irradiation, as reported by Troxell and Watkins (1979), who find donorlike and acceptorlike levels —0.1 eV from the band edges. 

Figure 13 Pressure effect on the room-temperature luminescence spectrum of samarium(II) doped into SrFCl (reproduced by permission of Springer-Verlag from Top. Curr. Chem. 2001, 213, 1-94).

Morita S, Zakhidov AA, YosMno K (1992) Doping effect of buckminsterftjlleiBne in conducting polymer change of absorption spectrum and quenching of luminescence. Solid State Commun 82 249-252. doi 10.1016/0038-1098(92)90636-N... 

External perturbations, such as pressure or electric and magnetic fields, discussed in Chapters 2.23 and 2.25, often lead to dramatic optical spectroscopic effects. An example is the luminescence of samarium(II) ions doped into SrFCl shown in Figure 13, where pressure induces a large change in the spectrum. Between ambient pressure and 67 kbar, the expected intracon-figurational luminescence transitions are observed as narrow lines. They show a... 

The combined effect of a large increase in the energy of the 2g shite and essentially no change in the energy of the Eg state with pressure is responsible for the observed electronic crossover. The change from a spin-allowed 2g emission to a spin-forbidden Eg A2g emission leads to the observed transformation from a smooth, broadband emission spectrum to a sharp, structured emission spectrum. The " T2g- Eg crossover was observed in many materials. The latest reviews on high-pressure spectroscopy of the Cr " -doped materials can be found in [81, 87]. A typical example is presented in Fig. 4.6a-e where the luminescence spectra and luminescence decays of the LiSc(W04)2 Cr system, obtained at different pressures between ambient and 260 kbar, are presented. As... 

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