Luminescent properties of Mn and Cr doped Al 2 O 3 single crystalline films under excitation with synchrotron radiation

Excitation with synchrotron radiation has provided a powerful means to study the intrinsic and dopant-related luminescent phenomena of wide bad -gap dielectrics. In this study, the luminescent properties of Mn- and Crdoped single crystalline films of alpha-Al 2 O 3 (sapphire), grown using the liquid phase epitaxy method from PbO -B 2 O 3 flux onto C plane-oriented sapphire crystal substrates, were systematically investigated using absorption and cathodoluminescence spectra as well as the conventional and advanced photoluminescent spectroscopy under synchrotron radiation excitation. The emission and excitation spectra have shown characteristic bands corresponding to Mn 4 + and Cr 3 + impurities as well as Pb 2 + flux-related dopants and indicated the participation of these metal ions in the luminescence process. The influence of the excitation energy in the transparency region and exciton range of the Al 2 O 3 host on the intensity and spectral shape of the emissions bands of these dopants is discussed in detail. The obtained results contribute to understanding the application potential of Al 2 O 3 :Mn and Al 2 O 3 :Mn single crystalline films in optoelectronic devices and luminescent sensors.