X-ray diffraction study of thin electroluminescent ZnS films grown by atomic layer epitaxy

Abstract

Structural properties of electroluminescent ZnS:Mn thin films emitting yellow light with an external efficiency as high as 2% are investigated. X-ray diffraction patterns show that the ZnS films grown directly on glass or on thin Al2O3 or Ta2O5 substrates (on glass) at 500°C using atomic layer epitaxy method are polycrystalline and mainly hexagonal. They have a strong preferred orientation: one half of the 00.1 plane normals are aligned within 7° from the normal of the glass substrate. The length of coherently diffracting domains (crystallite size) in the direction of the normal obtained from the Fourier analysis of a line profile ranges from 30 to 160 nm. The average relative strain in the same direction is calculated to be 10−3.