Photoluminescence emission spectroscopy and electrical transport measurements have been employed to study the origin and roles of oxygen impurities in hexagonal boron nitride (h-BN) epilayers grown on sapphire substrates. The temperature dependence of the electrical resistivity revealed the presence of a previously unnoticed impurity level of about 0.6 eV in h-BN epilayers grown at high temperatures. The findings suggested that in addition to the common nitrogen vacancy (VN) shallow donors in h-BN, oxygen impurities diffused from sapphire substrates during high temperature growth also act as substitutional donors (ON). The presence of ON gives rise to an additional emission peak in the photoluminescence spectrum, corresponding to a donor-acceptor pair recombination involving the ON donor and the CN (carbon occupying nitrogen site) deep level acceptor. Moreover, due to the presence of ON donors, the majority charge carrier type changed to electrons in epilayers grown at high temperatures, in contrast to typical h-BN epilayers which naturally reflect “p-type” character. The results offered a more coherent picture for common impurities/defects in h-BN as well as a better understanding of the growth mediated impurities in h-BN epilayers, which will be helpful for finding possible ways to further improve the quality and purity of this emerging material.
Grenadier, S. J., Maity, A., Li, J., Lin, J. Y., & Jiang, H. X. (2018). Origin and roles of oxygen impurities in hexagonal boron nitride epilayers. Applied Physics Letters, 112(16). https://doi.org/10.1063/1.5026291
Grenadier, S. J., Maity, A., Li, J., et al., "Origin and roles of oxygen impurities in hexagonal boron nitride epilayers," Applied Physics Letters 112, no. 16 (2018), https://doi.org/10.1063/1.5026291
@article{osti_1540187,
author = {Grenadier, S. J. and Maity, A. and Li, J. and Lin, J. Y. and Jiang, H. X.},
title = {Origin and roles of oxygen impurities in hexagonal boron nitride epilayers},
annote = {Photoluminescence emission spectroscopy and electrical transport measurements have been employed to study the origin and roles of oxygen impurities in hexagonal boron nitride (h-BN) epilayers grown on sapphire substrates. The temperature dependence of the electrical resistivity revealed the presence of a previously unnoticed impurity level of about 0.6 eV in h-BN epilayers grown at high temperatures. The findings suggested that in addition to the common nitrogen vacancy (VN) shallow donors in h-BN, oxygen impurities diffused from sapphire substrates during high temperature growth also act as substitutional donors (ON). The presence of ON gives rise to an additional emission peak in the photoluminescence spectrum, corresponding to a donor-acceptor pair recombination involving the ON donor and the CN (carbon occupying nitrogen site) deep level acceptor. Moreover, due to the presence of ON donors, the majority charge carrier type changed to electrons in epilayers grown at high temperatures, in contrast to typical h-BN epilayers which naturally reflect “p-type” character. The results offered a more coherent picture for common impurities/defects in h-BN as well as a better understanding of the growth mediated impurities in h-BN epilayers, which will be helpful for finding possible ways to further improve the quality and purity of this emerging material.},
doi = {10.1063/1.5026291},
url = {https://www.osti.gov/biblio/1540187},
journal = {Applied Physics Letters},
issn = {ISSN 0003-6951},
number = {16},
volume = {112},
place = {United States},
publisher = {American Institute of Physics (AIP)},
year = {2018},
month = {04}}
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 748https://doi.org/10.1016/j.nima.2014.02.031