STRUCTURAL, OPTICAL AND ELECTRONIC PROPERTIES OF In1-xYxN THIN FILMS

The study of IIIA-IIIB-V type thin films has recently been receiving a great deal of attention as possible solutions to optimize and to further engineer the electronic, optical and structural properties of optoelectronic materials. In this work we studied the influence of yttrium addition to InN films, in connection with YN band-gap, and explored the possibility of tuning the optical and electronic properties of In1-xYxN thin films for low concentration of yttrium. Reactive sputtering method was used in this work to grow thin films of In1-xYxN with low yttrium concentrations, 0 ≤ x ≤ 0.094, as well as of a pure YN (x = 1), on fused quartz substrates at 500 C. At low Y contents (0 ≤ x < 0.1), the wurtzite structure of InN was preserved. In1-xYxN films exhibited the specific alloy-type behavior of the compound with linear variation of the lattice constants, optical band-gap, carrier mobility and surface roughness with the Y content. Encouraging evidences for tuning the electron concentration in In1-xYxN thin films were observed. YN films were obtained in a rock-salt structure, with an indirect band-gap of about 0.498 eV, which represent, up to our knowledge, the first experimental evidence of the existence of the indirect optical bandgap in c-YN.