Growth of ZnS: Tm thin films by MOCVD

Thin films of thulium-active ZnS have been deposited on ITO coated glass su bstrates by a low-pressure vertical metalorganic chemical vapor deposition (MOCVD) system. Dimethylzinc (DMZn) and hydrogen sulfide (H2S) are used as reactants, and Tris(hexafluoroacetonato-thulium) (Tm(HFAA)(3), molecular fo rmula Tm(C5HF6O2)(3)) is used as dopant source. Energy dispersive spectrome ter (EDS), X-ray diffraction (XRD), scanning electron microscopy (SEM), Aug er electron spectra (AES), and secondary ion mass spectra (SIMS) were used to determine the elemental composition, surface morphologies and depth prof iles. Optical properties of ZnS:Tm thin films were characterized by photo-l uminesence (PL). The best growth conditions are substrate temperature at 22 5 degrees C, DMZn bubbler temperature at - 8 degrees C, Tm(HFAA), bubbler t emperature at 70 degrees C, growth pressure at 30 Torr, flow rate of DMZn 2 .5 x 10(-5) mol/min, flow rate of H2S 5 x 10(-4) mol/min, flow rate of Tm(H FAA), 0.1 SLM, and VI/II molar ratio of 20. (C) 2000 Elsevier Science B.V. All rights reserved.