High Resolution X-Ray Diffraction and Raman Scattering Studies of Cubic-Phase InN Films Grown by MBE

Abstract

We demonstrate the use of high resolution X-ray diffraction and Raman scattering to assess the generation of hexagonal-phase in the cubic-phase InN (c-InN) films on MgO substrates grown by molecular beam epitaxy with a cubic-phase GaN buffer layer. The X-ray reciprocal-lattice space mapping was used to examine the hexagonal-phase generated on the cubic (111) planes in the c-InN films. Ratio of hexagonal to cubic components in the c-InN grown layers was estimated from the ratio of the integrated X-ray diffraction intensities of cubic (002) and hexagonal (10-11) reflections measured by ω-scans. Amount of hexagonal-phase presented in the c-InN films was determined in the range of 6 to 24%. It was found that the Raman characteristics are also sensitive to hexagonal-phase presented in the c-InN films. For the lowest amount of hexagonal-phase (6%), only Raman scattering characteristics of c-InN was observed, indicating formation of a small amount of stacking faults, which not affected on the vibrational property. Based on our results, relatively easy access to the generation of hexagonal-phase suggests that it may be very useful for HRXRD and Raman scattering measurements of c-InN.

High cubic phase purity of ELOG cubic GaN on [110] mask‐stripe‐patterned GaAs (001) substrates by MOVPE

“…Unlike previous reports , the values of the weight factor are found to depend on the film thickness with exponential decay. They are also influenced by the diffraction geometry factor, which is different under positive and negative ‐offset conditions.…”

“…To give a quantitative result of hexagonal phase inclusions in the ELOG c‐GaN films, the ratio of the integrated X‐ray intensities of the h‐GaN and c‐GaN reflections detected by X‐ray RSMs were investigated by ω‐scans . For a large variation of film thickness in the range of 1.4 to 12 μm, the extinction distance of the X‐ray beam may be very different for the different reflections.…”

“…To verify the hexagonal phase inclusion, which is constructed on the planes, in the ELOG c‐GaN films, a symmetric reciprocal space mapping (RSM) was investigated around cubic and hexagonal reflections with the X‐ray incident beam both perpendicular and parallel to the mask‐stripe direction. A volume amount of hexagonal phase inclusion is estimated from the ratio of the integrated XRD intensities of the cubic and hexagonal reflections measured by ω‐scan, which are extracted from the RSMs . As the films examined range in thickness from 1.4 to 12.0 μm, the extinction distance of the X‐ray beam may be very different for the different reflections .…”

Metastable cubic InN layers on GaAs (001) substrates grown by MBE: Growth condition and crystal structure

“…This suggests that the higher crystal quality c-InN layers can be achieved by the MBE growth under In-rich conditions. To estimate the volume amount of the hexagonal phase inclusion in the c-InN layers, the ratio of the integrated XRD intensities of the cubic (002) and hexagonal (1-101) planes measuring by ω-scan [14,15] was used. It is found out that the hexagonal-phase generation significantly depends on the growth condition.…”