Preparation and mechanoluminescent properties of SrAl2O4:Eu film grown on silicon substrate using double buffer layers

• Double-layer method used to prepare SrAl2O4:Eu film on silicon substrate (400).
• SrAl2O4:Eu film with excellent photoluminescent and mechanoluminescent properties
• The film can be used as an indicator to detect stress distribution of an object.

In this paper, we utilized double layer method to prepare SrAl2O4:Eu (SAOE) film on silicon substrate (400). The Al2O3 layer (about 200 nm) was used as a hetero-buffer layer to eliminate the large difference of crystal lattice and thermal mismatch between the SAOE and silicon substrate. Thin SAOE layer (about 600 nm) was grown on Al2O3 layer as homo-buffer layer to reduce internal stress during film growth process. On double buffer layers, continuous sputtering formed about 1.5 μm SAOE film. The resulting thick SAOE/Al2O3/Si film possessed both excellent photoluminescence (PL) and mechanoluminescence (ML) properties. The similarity of PL and ML spectra suggested that PL and ML both originated from same emitting center of Eu2 +. The strong ML intensity showed that the as-prepared SAOE film can be regarded as an indicator to detect stress distribution of an object. The thermoluminescent (ThL) results indicated that a large amount of trapped electrons existing in the resulting film answered for the strong ML intensity.