Probing Boron Vacancy Complexes in h-BN Semi-Bulk Crystals Synthesized by Hydride Vapor Phase Epitaxy

Abstract

Hexagonal BN (h-BN) has emerged as an important ultrawide bandgap (UWBG) semiconductor (Eg~6 eV). The crystal growth technologies for producing semi-bulk crystals/epilayers in large wafer sizes and understanding of defect properties lag decades behind conventional III-nitride wide bandgap (WBG) semiconductors. Here we report probing of boron vacancy (VB)-related defects in freestanding h-BN semi-bulk wafers synthesized by hydride vapor phase epitaxy (HVPE). A photocurrent excitation spectroscopy (PES) was designed to monitor the transport of photoexcited holes from deep-level acceptors. A dominant transition line at 1.66 eV with a side band near 1.62 eV has been directly observed, which matches well with the calculated energy levels of 1.65 for the VB-H deep acceptor in h-BN. The identification of VB complexes via PES measurement was further corroborated by the temperature-dependent dark resistivity and secondary ion mass spectrometry measurements. The results presented here suggested that it is necessary to focus on the optimization of V/III ratio during HVPE growth to minimize the generation of VB-related defects and to improve the overall material quality of h-BN semi-bulk crystals. The work also provided a better understanding of how VB complexes behave and affect the electronic and optical properties of h-BN.

Description

© 2023 by the authors. cc-by

Keywords

Deep Level Defects, Hexagonal Boron Nitride, Hydride Vapor Phase Epitaxy, Neutron Detectors, Photocurrent Excitation Spectroscopy, Ultrawide Bandgap Semiconductor

Citation

Alemoush, Z., Tingsuwatit, A., Li, J., Lin, J., & Jiang, H.. 2023. Probing Boron Vacancy Complexes in h-BN Semi-Bulk Crystals Synthesized by Hydride Vapor Phase Epitaxy. Crystals, 13(9). https://doi.org/10.3390/cryst13091319

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