Hydrogen-nitrogen complexes in dilute nitride alloys: origin of the compressive strain

Hydrogenation of GaAs1-xNx and GaP1-xNx epilayers grown on GaAs(001) and GaP(001) surfaces, respectively, is known to passivate the electronic activity of nitrogen through the formation of specific nitrogen-hydrogen complexes. The same epilayers also undergo a strain reversal from tensile (as grown) to compressive (fully hydrogenated). The authors show that the extent of strain reversal is determined exclusively by the nitrogen concentration. By performing in situ high resolution x-ray diffraction measurements during annealing and photoluminescence studies, the authors demonstrate that the lattice properties of fully hydrogenated GaAs1-xNx are ruled by a H complex, which is different and less stable than that responsible for electronic passivation of nitrogen in GaAs1-xNx.