Keele Research Repository

We report a comparative synchrotron radiation x-ray diffraction study of GaAs1−yNy micro-structures obtained by two different patterning methods: spatially selective H incorporation achieved by using H-opaque masks and spatially selective H removal attained by laser writing. These methods are emerging as original routes for fabrication of micro- and nano-structures with in-plane modulation of the bandgap energy. By measuring the out-of-plane and in-plane lattice parameters, we find that for both patterning approaches the largest part of the micro-structure volume remains tensile-strained and pseudomorphic to the substrate, regardless of the compressive-strained hydrogenated barriers. However, a larger lattice disorder is probed in the laser-written micro-structures and attributed to partial removal of H and/or strain changes at the micro-structure boundaries. This larger lattice disorder is confirmed by photoluminescence studies.

We thank Synchrotron SOLEIL for general facilities placed at our disposal. The experiment at the SIRIUS beamline was performed during in-house research time. We are grateful for technical support by Mr. N. Aubert. We acknowledge S. Rubini and F. Martelli for providing the samples. G.P., M.F., and A.Po. acknowledge funding from the Italian MIUR (under FIRB project DeLIGHTeD). A.Po. acknowledges funding by Sapienza Università di Roma under the “Ateneo 2013” grant.