Investigation of Oxygen-Related Luminescence Centres in AlN Ceramics

Abstract

The structure of oxygen‐related luminescence centres in nominally undoped and Y2O3 doped AlN ceramics was investigated by electron paramagnetic resonance (EPR), electron nuclear double resonance (ENDOR) and optically‐detected EPR. The photoluminescence‐detected EPR lines having g‐values of 1.990 and 2.008 were assigned to a recombination between neighbouring donor and acceptor pairs. The two EPR lines at g = 1.987 and 2.003 detected via the recombination luminescence in the afterglow are thought to be due to a recombination between the same, but distant donor and acceptor pairs. The donor was previously speculated to be an electron trapped on an oxygen impurity which substitutes for a nitrogen on a regular lattice site. The defect structure of the acceptor was established by ENDOR to be a hole trapped on an ON–vAl complex (ON oxygen on a regular N site, vAl Al vacancy). The measured superhyperfine interaction is caused by two equivalent 27Al nuclei both with a = ±27.0 MHz.

Spectral Characteristics of Native Defects in BN

“…A behavior of 2.5 eV PL in BN is very close to that of 3.1 eV PL observed for AlN [5,6]. In the case of AlN the defects, which are responsible for the 3.1 eV PL are revealed [7] as the oxygen-related defects. Oxygen ions depending on their nearest environment in the crystalline lattice form both the donor and acceptor centers under UV-light irradiation.…”

AlN Ceramics from Nanosized Plasma Processed Powder, its Properties and Application

“…In this paper, we will pay attention mostly to properties of luminescence produced by UV light irradiation, as well as stop briefly on luminescence properties produced by ionizing radiation, which potentially can be used in dosimetry. The experimental results mentioned in this chapter are described in detail in our previous works [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41].…”

“…The pioneers of AlN investigation, Slack [43] and Harris [44], had found that the UV emission band is due to the presence of oxygen-related defects containing oxygen ion substituting for nitrogen O N and aluminum vacancy v Al ; besides, position of the band varies in the 370-400 nm range depending on concentration of oxygen impurity. According to electron paramagnetic resonance (EPR) and electron-nuclear double resonance spectroscopy (ENDOR) studies [29], the UV band occurs as a result of radiative recombination of two close oxygen-related defects: (i) O N -v Al and (ii) another O N . Model of these defects is shown in Figure 9.15.…”

“…Model of these defects is shown in Figure 9.15. Though there are also alternative interpretations of the UV band's nature, like the assumption [45] implying radiative recombination between an unknown shallow donor and an isolated Al vacancy (v 3− Al ), hereafter we will adhere to the assignment of the UV emission band proposed in [29] taking into account dependence of the UV band on oxygen concentration.…”

Luminescence Properties of AlN Ceramics and Its Potential Application for Solid State Dosimetry

“…Presence of the emission band in PL, TL and OSL as well as afterglow emission and time characteristics of its intensity speak in favor in its recombination character. The nature of the 400 nm subband was determined by the EPR and ENDOR studies (Schweizer et al, 2000) as recombination luminescence of two defect centers: a donor -(O N -v Al ) -a complex defect center formed by an oxygen ion substituting for nitrogen ion O N in a regular site and a neighboring aluminum vacancy v Al and an acceptor -another closely situated oxygen ion O N . The luminescence mechanism responsible for the 400 nm emission band in AlN ceramics, was formulated in papers (Berzina et al, , 2009 (Berzina et al, 2009).…”