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The addition of a small percent of nitrogen to GaAs causes a large reduction of the band gap energy and a tensile strain within the lattice. The further addition of H at 300 C causes a recovery of the band gap of the N-free GaAs host. Concomitantly, tensile strain turns into compressive strain. Upon reduction of hydrogenation temperature, high-resolution x-ray diffraction studies show now a remarkable increase of compressive strain, while photoluminescence measurements show that the recovered band gap energy of GaAs does not change. Infrared measurements indicate that several NH n centers are formed in addition to the well-established HNH center (n= 2), which accounts for the band gap recovery. The vibrational properties of the corresponding deuterium centers provide clues to the microscopic structures of these centers. Furthermore, theory shows that the center with n= 2 is robust when additional H is …
American Physical Society
Publication date: 
22 Aug 2012

L Wen, M Stavola, WB Fowler, R Trotta, A Polimeni, M Capizzi, G Bisognin, M Berti, S Rubini, F Martelli

Biblio References: 
Volume: 86 Issue: 8 Pages: 085206
Physical Review B