Studies on polycrystalline ZnS thin films grown by atomic layer deposition for electroluminescent applications

Polycrystalline ZnS thin films were grown by the atomic layer deposition (ALD) using the precursors of diethyl zinc and hydrogen sulfide in the substrate temperature range of 250-400 degreesC. The most uniform ALD growth was observed at 300 T with the growth rate of 0.7 Angstrom per cycle. Atomic constituent analyses confirmed that as-deposited ZnS films were stoichiometric and contained no impurities of detectable amount. X-ray diffraction measurements revealed that crystalline structures were predominantly cubic in the temperature range of 250-350 degreesC and additional hexagonal phases began to appear at 400 degreesC. The dependence of surface morphology and crystalline microstructure on the ALD cycle number had also been investigated by using atomic force microscopy (AFM), cross-sectional transmission electron microscopy (TEM), and angle-resolved X-ray photoelectron spectroscopy (ARXPS). (C) 2004 Elsevier B.V. All rights reserved.