Thin film formation by rf sputtering with EuGa2S4 target and photoluminescence of the prepared films

Thin films were deposited on Si and fused quartz substrates by rf sputtering with EuGa2S4 target. The deposited films were annealed in the mixed atmosphere of S and He, which led crystallization of the film from amorphous phase. Photoluminescence of the annealed films, characteristic to the Eu2+ ion, was observed with room temperature quantum efficiency of 17%. Decay time constants at room temperature and liquid nitrogen temperature were measured to be 140 ns, and 430 ns, respectively. The latter value is close to the reported radiative lifetime of the EuGa2S4 crystal. Construction possibility of a surface-emitting laser is discussed with data on behaviour of excitation intensity dependent time-resolved spectra under pulsed laser excitation and on surface roughness of the film. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)