KŘENEK Tomáš University of West Bohemia, New Technologies Research Centre

IR Laser CVD of Nanodisperse Ge–Si-Sn Alloys Obtained by Dielectric Breakdown of GeH4/SiH4/SnH4 Mixtures

Nowadays, great attention is devoted to Ge-Si-Sn ternary system, because Si1-x-yGexSny provides the potential of band gap engineering and tuning of the optical properties. IR laser irradiation of equimolar gaseous GeH4 + SiH4 + SnH4 + Ar mixture results in simultaneous decomposition of all three compounds and it allows deposition of nanostructured solid film. Analysis of the films by FTIR and Raman spectroscopy, X-ray diffraction analysis and electron microscopy revealed crystalline nanobodies of pure β-Sn and crystalline nanoobjects of Ge1−x−ySixSny embedded in an amorphous metastable Ge-Si-Sn alloy. This process allows co-decomposition of all silicon, germanium and tin hydrides which is caused by combination of infrared multiple photon dissociation of absorbing silane and currently proceeding LIDB. This is followed by intermixing/clustering of extruded metal atoms in the gas phase.