Effects of annealing on 320 nm cathodoluminescence from hexagonal boron nitride powders

Abstract

The effect of annealing in various atmospheres (N2, H2, NH3 O2 and vacuum) on the 320 nm emission bands of hexagonal boron nitride (h‐BN) powders has been investigated by cathodoluminescence (CL). The CL intensity was decreased by annealing in the N2, H2and NH3 atmospheres at 1200 °C, with H2and NH3 having more effect than N2. On the other hand, the annealing in the O2 atmosphere increased the CL intensity remarkably at annealing temperatures higher than 800 °C. These results suggest that the oxygen located near the particle surface is related to the enhancement of the 320 nm bands in h‐BN. The highest CL intensity, which was obtained at an annealing temperature of 900 °C, reached to about one third of that measured for ZnS:Cu,Al phosphor under the same measurement conditions. The investigation of the powder annealed at higher temperatures in a vacuum indicated that the luminescent centers responsible for these emission bands are thermally stable up to about 1300 °C (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Hexagonal boron nitride luminescence dependent on vacuum level and surrounding gases

“…Also phonon-assisted luminescence at 320 nm could be used for flat-panel lamps and electron emitters [16]. Besides, as shown in our previous work [17] the luminescence around 400 nm shows gas sensing properties.…”

Temperature effects in 3.9 eV photoluminescence of hexagonal boron nitride under band-to-band and subband excitation within 7–1100 K range

“…24,25 Besides, the Ref. 26 showed that annealing of an h-BN micropowder in an O2 atmosphere at a temperature of 900 °C for 2 h results in an increase in both the oxygen content from 0.25 to 0.40 wt. % and the intensity of cathodoluminescence in the 320 nm (3.9 eV) band by almost 4 times as compared to the initial sample.…”

Room-temperature intrinsic excitonic luminescence from a hexagonal boron nitride thin film grown on a sapphire substrate by low-pressure chemical vapor deposition using BCl3 as a boron source

“…25,29) The possibility of an oxygen impurity as the origin of this emission has also been discussed on the basis of the luminescence property of the oxygen-annealed h-BN powders. 30,31) On the other hand, the origin of the latter emission band is not clear at present. The dependences of CL spectra and XRD patterns on the growth temperature for the samples grown at 20 kPa suggested that the broad emission at about 350 nm is correlated with the disordered BN.…”