Photoluminescence of electrochemically etched porous silicon coated with small-molecule based thin organic films

In this paper, photoluminescence (PL) spectra of porous silicon (PSi) prepared by electrochemical anodisation coated with small-molecule based thin organic films are presented. Thin layers of copper phthalocyanine (CuPc) and tris(8-hydroxyquinoline) aluminium (Alq3) were deposited on PSi using the conventional thermal evaporation in high vacuum. Presented structures exhibit strong photoluminescence in visible region at room temperature under pulsed UV excitation. PL spectra of Alq3 deposited on glass and PSi layer without organic film are presented for intercomparison. The shapes of PL spectra of PSi/organic structures depends on material used and exhibit multiband structure. Properties of PSi/organic luminescence can be explained by penetration of organic material into PSi skeleton and interaction between carriers in PSi and deposited material.