Spectral and kinetic features of thermoluminescence in hexagonal boron nitride powder after UV-irradiation

Thermally stimulated luminescence (TL) from UV-irradiated h-BN powder synthesized using carbamide technique was studied. Three TL peaks at Tmax = 380, 500 and 600 K during linear heating with 2 K/s rate in RT – 773 K temperature range were observed. It was found that the 2.90 and 3.25 eV emission bands, which were related with recombination centers on the basis of VN and BO−-complexes, dominate in TL spectra of h-BN. Experimental TL glow curves were analyzed in terms of general order kinetics and energy parameters of responsible capture levels were estimated. It was shown, considering the independent data on the luminescent properties of hexagonal boron nitride in different structural states, that TL peaks at 380 K and 600 K were due to traps based on the one-boron and the three-boron centers with thermal depth EA = 0.7 and 1.0 eV, respectively. The possible origin of the trap with EA = 1.6 eV, responsible for the TL peak at 500 K, is discussed.

► UV-irradiated h-BN powder is characterized by three TL peaks in different spectral regions.
► TL peaks at 380 and 600 K are caused by capture levels of one-boron and three-boron centers, respectively.
► Visible range emissions of vacancy centers and oxygen–boron complexes dominate in thermoluminescence of h-BN.