Cathodoluminescence of oxygen-vacancy centers in structures of aluminum nitride

Slow decay of a defect‐related emission band at 2.05 eV in AlN: Signatures of oxygen‐related DX states

“…The latter assignment was also suggested by Spiridonov et al. for a cathodoluminescence (CL) emission band at 2.1 eV observed in bulk single crystals also grown by PVT .…”

“…Based on their Xray diffraction, field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, and energy dispersive Xray spectroscopy results and on earlier publications, they assigned the 3.2 eV emission to a DAP transition from O N to V Al -O N , and the 2.0 eV emission to a transition from the aluminum vacancy V Al to the valence band [44]. The latter assignment was also suggested by Spiridonov cathodoluminescence (CL) emission band at 2.1 eV observed in bulk single crystals also grown by PVT [45]. Sedhain et al [23] found a luminescence band which consists of two clearly distinguishable contributions at 1.88 and 2.09 eV at 10 K. The contribution at around 1.88 eV does not change the energy position by increasing the sample temperature, but the contribution at around 2.09 eV shifts blue, what cannot be observed for our sample.…”

Cathodoluminescence of aluminum ceramic compounds

“…16,19,20 Different assumptions can be proposed to explain the origin of the emission band at ∼2.05 eV. [14][15][16] Schulz et al have theoretically predicted the existence of an energy level [Al vacancies (v Al ) 3− ] at about 2.0 eV above the Valence Band Edge (VBE). 17 Negatively charged vacancies actually act as attractive centers for holes.…”

“…During electron excitation, holes are generated in the VB (Valence Band) and transitions of electrons from the defect state (v Al ) 3− to the VB become possible. 14 The (v Al ) 3− + h → (v Al ) 2− process results in an emission peak at ∼2.05 eV.…”

Engineering visible light emitting point defects in Zr-implanted polycrystalline AlN films

“…Theoretical and experimental results showed that VN and VAl point defects have shallow energy levels below the conduction band and above the valence band extrema, respectively [52,53]. Oxygen substitutional defect (ON) and their related defect complexes, such as VAl -ON, have also been reported as an important defect in AlN [54][55][56][57][58]. Based on these studies and other DFT calculations [19][20][21]59], the suggested origin of the different emission bands is given in Table 2 showing also the optical transition schemes involving these most common defects.…”