Biexcitonic behavior of 1s yellow exciton in Cu 2 O microcrystallites embedded in solution-derived nano-zirconia film matrix

Abstract

Cu20 microcrystallites of the size range 55-73 A were embedded in the nano-zirconia thin film matrix f precursor contains zirconium oxychloride octahydrate and cupric nitrate trihydrate. Absorption and fi uorescence spectra of the films annealed at different temperature, 200°-1200°C revealed that the microcrystallites are possessing both mono-and biexcitonic behaviours which are dependent on microcrystallite size. Maximum biexcitonic behaviour has been predicted in the case of450°C annealed sample (size 69 A, cal.) which also showed phosphorescence possibly due to inter-crossing of potential energy curve of Cu20 exciton and 3D offreeThe anisotropic nature ofthe excitonic transitions ofCu2O was also observed due to electrical quadrupole fransition which was authenticated by its emission and ESR spectral studies.