An Influence of X-Ray Irradiation on Mid-Bandgap Luminescence of Boron Nitride Epitaxial Layers

M. Szoła, M. Tokarczyk, G. Kowalski, J. Binder, K. Pakuła, A. Dąbrowska, A. Wysmołek, J. Łusakowski Institute of Experimental Physics, Faculty of Physics, University of Warsaw, L. Pasteura 5, PL-02093 Warsaw, Poland

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Samples of boron nitride (BN) in the form of an exfoliated monolayer, epitaxial layers grown on sapphire, and a powder with micrometer grains were studied in a luminescence experiment connected with irradiation of samples with X-rays. The luminescence excited with photons with the wavelength of 488 nm was shown to span over a broad band from a filter cut-off at 550 nm to about 850 nm. The intensity of luminescence showed a monoexponential decrease both before and after irradiation with X-rays, but this dynamics slowed down after irradiation to an extent dependent on the X-ray dose. This indicates possible application of BN in dosimetry of X-rays. An influence of sapphire substrates on photoluminescence dynamics was also studied. We show that this influence is very strong in the case of layers with thickness of a few nm and can be disregarded when the thickness is equal to a few tens of nm.

DOI:10.12693/APhysPolA.136.620 topics: Boron nitride, X-Ray, Luminescence, Dosimetry