(a) -scan XRD patterns of InN thin films grown on LAO substrates with different growth conditions (summarized in Table I). (b) XRCs of pure -plane InN (sample D) taken along -axis and -axis  directions. The FWHM measured along -axis direction shows strong index dependence. (c) - and (d) -oriented RHEED patterns of the -plane InN. Both XRCs and RHEED patterns of the -plane InN reveal strong structural anisotropy.
Field-emission electron microscope images, electron back scatter diffraction (EBSD) patterns, and atomic models of (a), (c), and (e), -plane InN columnar film (sample C) and (b), (d), (f) -plane InN epifilm (sample D). The atomic models are generated from corresponding EBSD patterns by INCA software. The results show that the long-axis of the stripelike feature the -plane InN film is parallel and perpendicular to and -axis, respectively.
(a) TEM images of the pure -plane InN epifilm. (b) The corresponding SAED pattern. (c) and (d) High resolution lattice images taken at film and interface region, respectively. Single crystalline structure of the InN film is obtained except for some BPSFs. The inset in Fig. 3(c) shows type stacking faults, i.e., stacking sequence; A: white, B: black, and C: gray circles. The interface image clearly shows the epitaxial relationship of and , and commensurately lattice-matched condition between InN and LAO with a relation of equal to .
Ball-and-stick model of the -plane InN and the (100) face LAO. (a) Two rectangles coupled with blue or white balls at corners indicates the N and In nucleate on cation (O) and anion (Al, In) sites of LAO, respectively. (b) The epitaxial model plotted along direction exhibits the same commensurately lattice-matched condition between InN and LAO as observed from cross-sectional HRTEM image shown in Fig. 3(d).
(a) Polarized UV-Raman spectra of InN films measured at 0° with backscattering configuration, i.e., the laser polarization is parallel to  direction of LAO substrate. The Raman spectra are matched to and scattering configurations for - and -plane InN, respectively. (b) Integrated Raman intensities of mode with angle dependence plotted as a quarter pole figure. The -plane InN shows strong angle dependence.
Polarized PL spectra of -plane InN performed at 15 K. (a) Angle-dependent PL spectra of the -plane InN film. The laser polarization parallel to -axis of the film is set as 0°. (b) Corresponding intensities of the PL spectra plotted as a pole figure. Giant polarization degree of 87% is obtained.
Growth conditions of the InN films.
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