X-Ray Diffraction from Periodically Patterned GaAs Nanorods Grown onto GaAs[111]B

We present a high-resolution X-ray diffraction pattern of periodic GaAs nanorod (NR) ensembles and individual GaAs NRs grown catalyst-free throughout a prepatterned amorphous SiN (x) mask onto GaAs[111]B surfaces. The experiments were performed at a home laboratory using synchrotron radiation in combination with a micron-sized beam prepared by compound refractive lenses. The structural properties were probed by measuring RSMs (q (x) , q (z) ) in the vicinity of GaAs(111) and (222) reflections. Besides the GaAs substrate peak, we found a second peak referring to NRs with lattice mismatch of 0.23 pct with respect to the substrate, probably caused by structural defects. The lateral periodicity of NRs was probed by q (x) scans, and the NR height obtained from the width of the diffraction curve along q (z) . Grazing-incidence in-plane diffraction revealed the appearance of small crystallites of cubic gamma-Si3N4 caused by recrystallization of SiN (x) during NR growth. Whereas measurements at the home diffractometer provided average structure parameters, the micron-sized X-ray beam experiment was used to probe the parameters at individual NRs.