Growth control of ZnTe epitaxial thin films on Si (111)

Zinc telluride layers were directly grown on highly-lattice-mismatched Si (111) substrates by molecular beam epitaxy (MBE). Reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD) and atomic force microscopy (AFM) were used to study the growth mechanism and crystal quality of ZnTe on Si (111). The results show that the growth mode related with the VI/II beam pressure ratio is one of important factors affecting the initial growing process, crystal quality and morphology of ZnTe epitaxial thin films. From in situ RHEED observations, two-dimensional (2D) growth mode was found upon increasing VI/II beam pressure ratio to 3.3 while three-dimensional (3D) growth mode remained in Zn-rich atmosphere or at VI/II beam pressure ratio larger than 6. Small full-width at half-maximum (similar to 540 arcsec) showed that the growth of ZnTe on Si (111) in Te-rich atmosphere, especially in a layer-by-layer mode, was more suitable for nucleation growth.