Deposition of manganese-doped zinc sulfide thin films by the successive ionic layer adsorption and reaction (SILAR) method

Abstract

Manganese-doped zinc sulfide, ZnS: Mn, thin films were grown by the successive ionic layer adsorption and reaction method on glass, on ITO- and Al 2O 3-covered glass, and on quartz and CaF 2 using 0.1 M ZnCl 2, 0.05 M Na 2S and 0.01 M MnCl 2 as precursor solutions. The immersion time was 20 s and the rinsing time 100 s. The manganese was doped into the film by using separate ZnS and MnS deposition cycles. The desired Mn level (0.3–0.8 wt.%) in the ZnS film was achieved using a MnS ZnS cycle ratio of 1:100. The growth rate of the ZnS: Mn film was 0.09 nm cycle −1. The films were polycrystalline and presumably cubic. The appearance of the ZnS: Mn films, studied by scanning electron microscopy, was rougher than pure ZnS films but annealing for 3 h at 500 °C in a nitrogen atmosphere flattened the films. The refractive indices varied from 2.04 to 2.22 in films grown on glass and from 2.13 to 2.32 in those grown on ITO-covered glass. According to the Rutherford backscattering spectrometry and nuclear reaction analyses the ZnS: Mn films contained approx. 20 at.% oxygen and 3–15 at.% hydrogen, but their content was significantly reduced after annealing.