Heteroepitaxy of Hexagonal ZnS Thin Films Directly on Si (111)

Epitaxial wurtzite ZnS (W-ZnS) films were grown directly on Si (111) at temperatures as high as 800 C by PLD. A deconvolution method was used to discriminate the ZnS reflection from superimposed peaks overlapped by both ZnS and Si peaks in X-ray measurement. From the peak deconvolution, the rocking FWHM and lattice constant of the ZnS film were determined to be 0.28 degrees and 6.26 angstroms, resp. A tilt between W-ZnS and Si was observed and the tilt angle decreased with increasing growth temperature. The W-ZnS (0001) film on Si (111) showed the epitaxial relationship of Si [220]/ /ZnS[10-15]. An powder XRD scan along the L direction in reciprocal space and a high-resolution TEM image revealed that the W-ZnS film partially had stacking fault domains in the hexagonal phase. Free excitonic emission from the W-ZnS film was observed at 4 K. 20 refs.