Figure 1 | Theoretical investigation of self-recoverable ML emission in Al2O3:Cr3+. (IMAGE)
Caption
Figure 1 | Theoretical investigation of self-recoverable ML emission in Al2O3:Cr3+. a Crystal structure of Al2O3:Cr3+. b Calculated formation energies of CrAl defects under stress-free and stressed conditions. Self-consistent Fermi levels are indicated by vertical dashed lines. Local atomic structure: Cr atoms (blue spheres) and charge density distribution (yellow isosurfaces). c Electronic densities of states (DOS) for the ground-state CrAl0(4A2) defect under stress-free conditions, and the corresponding CrO6 octahedral structure (blue sphere: Cr; red sphere: O). Arrow diagram showing three electrons of Cr occupying the t2g energy level. d Electronic DOS for the ionized-state CrAl1+ defect under stressed conditions, and the corresponding CrO6 octahedral structure (blue sphere: Cr; red sphere: O). Arrow diagram showing two electrons of Cr occupying the t2g energy level. e Schematic diagram of the transitions between different states during electron excitation, relaxation, and recombination in Al2O3:Cr3+ in the ligand field. f Electronic DOS for the excited-state CrAl0(2E) defect under stress-free conditions, and the corresponding CrO6 octahedral structure (blue sphere: Cr; red sphere: O). Arrow diagram showing three electrons of Cr occupying the t2g energy level, one with opposite spin. g Upon strain excitation, bound excitons stored in activators are ionized and excited to CBM (process 1), followed by relaxation (process 2) and radiative recombination between electrons in the excited states and holes in the ground state (process 3). The driving forces (denoted as D) in this process include band bending, enhanced dipole moment, and enhanced electron–phonon coupling.
Credit
Dengfeng Peng et al.
Usage Restrictions
Credit must be given to the creator.
License
CC BY