Wednesday, 27 October 2021 15:50

Selective Effects of the Host Matrix in Hydrogenated InGaAsN Alloys: Toward an Integrated Matrix/Defect Engineering Paradigm

The local environmente plays a key role in determining the effective  concentration of N-H complexes. The local environmente plays a key role in determining the effective concentration of N-H complexes.

Article published on Advanced Functional Material.

In dilute nitride InyGa1−yAs1−xNx alloys, a spatially controlled tuning of the energy gap can be realized by combining the introduction of N atoms—inducing a significant reduction of this parameter—with that of hydrogen atoms, which neutralize the effect of N. In these alloys, hydrogen forms N–H complexes in both Ga-rich and In-rich N environments.
Here, photoluminescence measurements and thermal annealing treatments show that, surprisingly, N neutralization by H is significantly inhibited when the number of In-N bonds increases. Density functional theory calculations account for this result and reveal an original, physical phenomenon.

#dilute_nitride_alloys #density_functional_theory

In a joint experimental/theoretical work with CNR-ISM, Department of Physics UniSapienza, CNISM, CNR-IFN, Fondazione Bruno Kessler, Philipps University Marburg, Department of Physics and Materials Sciences Center, Marburg (Germany), Ecole Polytechnique Federale de Lausanne, Laboratory of Physics of Nanostructures, Lausanne (Switzerland) and Technion-Israel Institute of Technology, Department of Physics, Haifa (Israel), we investigated the reason why hydrogenation in InGaAsN alloys does not fully recovers band gap sistematically the same way it occurs in GaAsN alloys. In order to understand such a phenomenon we proposed to shift the focus from the defect itself to the effects induced by its environment.
While N-H defects form both in In-rich and Ga-rich environments, only in the In-rich N environment, the InyGa1−yAs host matrix exerts a selective action on the N–H complexes by hindering the formation of the complexes more effective in the N passivation.

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