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

Abstract

Transmission electron microscopy and high resolution X‐ray diffraction were applied to characterize the crystal structure and its modification in c‐InN layers on GaAs (001) substrates grown by rf‐plasma assisted molecular beam epitaxy. The layer quality was shown to depend on growth conditions, namely In‐ and N‐rich conditions. The best quality of c‐InN layers was achieved by “stoichiometric” growth under the In‐rich condition, resulting in In‐rich layers with a small amount of hexagonal‐phase inclusion (∼8%). On the other hand, nucleation and growth of N‐rich layers are shown to result in a high density of stacking faults which drastically decreases toward the InN surface. It is argued that the presence of stacking faults contributes to the structural modification in these layers. We found that the existence of a structural modification from cubic to mixed cubic/hexagonal phase in microstructure of the N‐rich layers exhibit higher hexagonal‐phase incorporation than that of the In‐rich layers. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

TEM Analysis of Structural Phase Transition in MBE Grown Cubic InN on MgO (001) by MBE: Effect of Hexagonal Phase Inclusion in an C-Gan Nucleation Layer

“…It is known that stable phase of InN is hexagonal structure, while the metastable phase is cubic structure, which is difficult to grow due to structural phase transform from cubic into hexagonal structures. This leads to a generation of planar defects, such as stacking faults (SFs) and twins along the (111) plane of cubic crystal [5,6,7]. Theoretically, the metastable c-InN is expected to have superior electronic properties, such as lower resistivity and lower electron effective mass because of its higher crystallographic symmetry, resulted in a reduction of electron phonon scattering [8].…”

Assessing structural, free-charge carrier, and phonon properties of mixed-phase epitaxial films: The case of InN

“…Due to the small tilt of this WZ InN semipolar plane, its XRD peak can not be detected in single XRD scans in Bragg-Brentano geometry. In reciprocal space mapping (RSM), the WZ phase inclusion may remain hidden depending on the azimuth angle [19]. Furthermore, a direct comparison of diffraction intensities of WZ(1011) and ZB(002) peaks can result in significant underestimation of the WZ phase content due to the much higher structural factor of the ZB InN (002) planes.…”