Structural Investigation of Cubic-Phase InN on GaAs (001) Grown by MBE under In- and N-Rich Growth Conditions

Abstract

We have investigated effect of the In- and N-rich growth conditions on the structural modification of cubic-phase InN (c-InN) films grown on GaAs (001) substrates by rf-plasmaassisted molecular beam epitaxy (RF-MBE). High resolution x-ray diffraction (HRXRD) and Raman scattering measurements were performed to examine the hexagonal phase generation in the c-InN grown films. It is evident that higher crystal quality c-InN films with higher cubic phase purity (~82%) were achieved under the In-rich growth condition. On the other hand, for the N-rich growth condition, the c-InN films exhibited higher incorporation of hexagonal phase, which is generated in the cubic phase through the incidental stacking faults on the c-InN (111) planes. Our results demonstrate that the In-rich growth condition plays a critical role in the growth of high quality c-InN films with higher cubic phase purity.

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

“…The horizontal axis ω is the tilted angle related to the rocking curve indicating crystal orientation and the vertical axis 2θ/ω is the diffraction angle related to the lattice spacing. The tilted angles between GaAs (002) plane and cubic (002) and hexagonal (10)(11) planes in the InN layers are 0° and ±7°, respectively. This demonstrates that the hexagonal-phase presented in the c-InN layers is mainly constructed on the cubic (111) surfaces and the crystal orientation relationship between hexagonal-phase inclusion and c-InN is hexagonal (0001)//cubic (111) [12,13].…”

“…The films were initially characterized by in-situ RHEED studies, scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). Such structural investigations were reported elsewhere [3,11]. It is known that, by adjusting the growth temperature and the supplied N 2 flow rate, the In-and Nrich films can be obtained.…”

“…3 Results and discussion The high quality c-InN layers were achieved by "stoichiometric" growth in term of supplied N 2 flow rate and growth temperature [3,11]. The term of "stoichiometric" is used here only in the situation of nucleation of a good c-InN layer under these growth conditions.…”

“…2 Experiment c-InN films discussed in this work were grown on GaAs (001) substrates by RF-MBE in a system described elsewhere [3,11]. Indium was evaporated from a Knudsen-type effusion cell.…”