Search citation statements
Paper Sections
Citation Types
Year Published
Publication Types
Relationship
Authors
Journals
The optical centers in AlN can frequently exist in various charge states and can be accompanied by many coexisting defect species, creating a complex environment where mutual interactions are inevitable. Therefore, it is an immediate quest to design AlN crystal growth protocols that can target a specific optical center of interest and tune its concentration while preventing the formation of other unwanted point defects. Here, we provide a powerful workflow for point defect engineering in wide band gap, binary semiconductors that can be readily used to design optimal crystal growth protocols through combining CALPHAD-based phase analysis, and ab initio defect calculations. We investigate technologically relevant chromium-and manganeseinduced optical centers in AlN, followed by studying the impact of oxygen that can be unintentionally incorporated during crystal growth. We present the dominant defects in all three cases as a function of process parameters along with the optical signatures. In the case of both Cr and Mn doping, the Cr Al and Mn Al defects are most likely, and increasing nitrogen partial pressure tends to enhance their concentration. We show that it is possible to use nitrogen fugacity as a tool for tuning the intensity of optical signatures. We calculate the Cr Al charge transition levels with respect to the valence-band maximum at 2.60 eV (E +/− ), 3.83 eV (E 0/− ), and 5.41 eV (E −/2− ) and electron and hole capture transitions with luminescence bands centered at 2.82, 1.91, and 3.15 eV. Unlike the Cr doping, Mn aggregation is unlikely, and the Mn Al −V N is the most abundant defect after Mn Al under most synthesis conditions. Oxygen tends to form complexes with V Al , and O N −V Al is a prominent defect following O N , with near-UV emission bands at 3.17, 3.26, and 3.81 eV. Our results agree with the available experimental optical signatures of Cr-, Mn-, and O-related centers and provide pathways on how to tune the luminous intensity of these centers through changes in growth conditions.
The optical centers in AlN can frequently exist in various charge states and can be accompanied by many coexisting defect species, creating a complex environment where mutual interactions are inevitable. Therefore, it is an immediate quest to design AlN crystal growth protocols that can target a specific optical center of interest and tune its concentration while preventing the formation of other unwanted point defects. Here, we provide a powerful workflow for point defect engineering in wide band gap, binary semiconductors that can be readily used to design optimal crystal growth protocols through combining CALPHAD-based phase analysis, and ab initio defect calculations. We investigate technologically relevant chromium-and manganeseinduced optical centers in AlN, followed by studying the impact of oxygen that can be unintentionally incorporated during crystal growth. We present the dominant defects in all three cases as a function of process parameters along with the optical signatures. In the case of both Cr and Mn doping, the Cr Al and Mn Al defects are most likely, and increasing nitrogen partial pressure tends to enhance their concentration. We show that it is possible to use nitrogen fugacity as a tool for tuning the intensity of optical signatures. We calculate the Cr Al charge transition levels with respect to the valence-band maximum at 2.60 eV (E +/− ), 3.83 eV (E 0/− ), and 5.41 eV (E −/2− ) and electron and hole capture transitions with luminescence bands centered at 2.82, 1.91, and 3.15 eV. Unlike the Cr doping, Mn aggregation is unlikely, and the Mn Al −V N is the most abundant defect after Mn Al under most synthesis conditions. Oxygen tends to form complexes with V Al , and O N −V Al is a prominent defect following O N , with near-UV emission bands at 3.17, 3.26, and 3.81 eV. Our results agree with the available experimental optical signatures of Cr-, Mn-, and O-related centers and provide pathways on how to tune the luminous intensity of these centers through changes in growth conditions.
Transition-metal centers exhibit a paramagnetic ground state in wide-bandgap semiconductors and are promising for nanophotonics and quantum information processing. Specifically, there is a growing interest in discovering prominent paramagnetic spin defects that can be manipulated using optical methods. Here, we investigate the electronic structure and magneto-optical properties of Cr and Mn substitutional centers in wurtzite AlN and GaN. We use state-of-the-art hybrid density functional theory calculations to determine level structure, stability, optical signatures, and magnetic properties of these centers. The excitation energies are calculated using the constrained occupation approach and rigorously verified with the complete active space configuration interaction approach. Our simulations of the photoluminescence spectra indicate that Cr Al 1+ in AlN and Cr Ga 1+ in GaN are responsible for the observed narrow quantum emission near 1.2 eV. We compute the zero-field splitting (ZFS) parameters and outline an optical spin polarization protocol for Cr Al 1+ and Cr Ga 1+ . Our results demonstrate that these centers are promising candidates for spin qubits.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.