Formation and dissolution of D-N complexes in dilute nitrides

• Published in: Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2007-11, Vol.76 (20), Article 205323
• Main Authors: Berti, Marina, Bisognin, Gabriele, De Salvador, Davide, Napolitani, Enrico, Vangelista, Silvia, Polimeni, Antonio, Capizzi, Mario, Boscherini, Federico, Ciatto, Gianluca, Rubini, Silvia, Martelli, Faustino, Franciosi, Alfonso
• Format: Article
• Language: English
• Subjects: ABSORPTION; ANNEALING; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CRYSTAL DEFECTS; DEUTERIUM; ELECTRONIC STRUCTURE; FINE STRUCTURE; GALLIUM ARSENIDES; HYDROGEN; IMPURITIES; LATTICE PARAMETERS; NITRIDES; NITROGEN; NITROGEN COMPLEXES; NUCLEAR REACTION ANALYSIS; PHOTOLUMINESCENCE; SEMICONDUCTOR MATERIALS; STRAINS; X RADIATION; X-RAY DIFFRACTION; X-RAY SPECTRA
• ISSN: 1098-0121; 1550-235X
• DOI: 10.1103/PhysRevB.76.205323

Deuterium (hydrogen) incorporation in dilute nitrides (e.g., GaAsN and GaPN) modifies dramatically the crystal's electronic and structural properties and represents a prominent example of defect engineering in semiconductors. However, the microscopic origin of D-related effects is still an experimentally unresolved issue. In this paper, we used nuclear reaction analyses and/or channeling, high resolution x-ray diffraction, photoluminescence, and x-ray absorption fine structure measurements to determine how the stoichiometric [D]/[N] ratio and the local structure of the N-D complexes parallel the evolution of the GaAsN electronic and strain properties upon irradiation and controlled removal of D. The experimental results provide the following picture: (i) Upon deuteration, nitrogen-deuterium complexes form with [D]/[N]=3, leading to a neutralization of the N electronic effects in GaAs and to a strain reversal (from tensile to compressive) of the N-containing layer. (ii) A moderate annealing at 250 deg. C gives [D]/[N]=2 and removes the compressive strain, therefore the lattice parameter approaches that of the N-free alloy, whereas the N-induced electronic properties are still passivated. (iii) Finally, annealings at higher temperature (330 deg. C) dissolve the deuterium-nitrogen complexes, and consequently the electronic properties and the tensile strain of the as-grown GaAsN lattice are recovered. Therefore, we conclude that the complex responsible for N passivation contains two deuterium atoms per nitrogen atom, while strain reversal in deuterated GaAsN is due to a complex with a third, less tightly bound deuterium atom.