Enabling the Ambient Pressure Growth of ScB2 Crystals for AlGaN Power Electronics
Abstract
Here we report the growth of single crystalline ScB2, an ultrahigh-temperature ceramic, at ambient pressure in a laser-heated Optical Floating Zone via the travelling solvent method. Crystals have been grown from both Sc-rich (55-65 at% Sc) and B-rich self-flux (80-83 at% B) at growth rates in the range of 0.2-2 mm/hr. The structure of grown crystals is in good agreement with an AlB2-type layered hexagonal phase, space group P6/mmm, with lattice constants a = 3.1423(2) Å (resp. 3.1502(3) Å) and c = 3.5084(3) Å (resp. 3.5041(3) Å) for crystals grown under Sc-rich (resp. B-rich) conditions. Crystals natively grow along the in-plane [100] direction. Electron backscattered diffraction shows that Sc-flux growth results in boules with multiple domains containing Sc inclusions, with the domains highly aligned. In contrast, B-flux boules are single domain after the initial nucleation region. Rocking-curve measurements of B-flux crystals for the (h000) and (000l) reflections show single peaks, establishing that the crystals are free from grain boundaries; the asymmetry in the scattered-intensity tails suggests the presence of point defects. Surface X-ray photoemission spectroscopy shows that the electronic environment in B-flux crystals is superior to that of Sc-flux crystals and produces highly resolved binding-energy peaks for B 1s and Sc 2p. Work-function measurements for the (11-20) plane give a value of approximately 5 eV, consistent with the highly electrically conductive nature of ScB2. These results demonstrate the viable ambient-pressure growth of ScB2, establish it as a lattice-matched substrate candidate for Al-rich AlGaN power microelectronics, and show that this growth route enables scalable manufacturing of ScB2 substrates.
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BibTeX
@misc{kushwaha2026enabling,
title = {{Enabling the Ambient Pressure Growth of ScB2 Crystals for AlGaN Power Electronics}},
author = {Satya K. Kushwaha and Ahamed Raihan and Astrid D. Kengne and Daniel Joel Harrison and R. Shipra and Han Xie and Evan N. Crites and Allana G. Iwanicki and Luke J. Meiler and Sharad Mahatara and Maxime A. Siegler and Renae N. Gannon and Steven R. Spurgeon and Rajeswari Kolagani and Amitayush Jhu Thakur and Stephan Lany and Patrick E. Hopkins and Jessica L. McChesney and Nancy Haegel and Tyrel M. McQueen and Michael G. Spencer and MVS Chandrashekhar},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.36493},
eprint = {2609.36493},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.36493},
}
RIS
TY - UNPB
TI - Enabling the Ambient Pressure Growth of ScB2 Crystals for AlGaN Power Electronics
AU - Satya K. Kushwaha
AU - Ahamed Raihan
AU - Astrid D. Kengne
AU - Daniel Joel Harrison
AU - R. Shipra
AU - Han Xie
AU - Evan N. Crites
AU - Allana G. Iwanicki
AU - Luke J. Meiler
AU - Sharad Mahatara
AU - Maxime A. Siegler
AU - Renae N. Gannon
AU - Steven R. Spurgeon
AU - Rajeswari Kolagani
AU - Amitayush Jhu Thakur
AU - Stephan Lany
AU - Patrick E. Hopkins
AU - Jessica L. McChesney
AU - Nancy Haegel
AU - Tyrel M. McQueen
AU - Michael G. Spencer
AU - MVS Chandrashekhar
PY - 2026
DA - 2026/09/29
PB - arXiv
DO - 10.48550/arxiv.2609.36493
UR - https://arxiv.org/abs/2609.36493
AB - Here we report the growth of single crystalline ScB2, an ultrahigh-temperature ceramic, at ambient pressure in a laser-heated Optical Floating Zone via the travelling solvent method. Crystals have been grown from both Sc-rich (55-65 at% Sc) and B-rich self-flux (80-83 at% B) at growth rates in the range of 0.2-2 mm/hr. The structure of grown crystals is in good agreement with an AlB2-type layered hexagonal phase, space group P6/mmm, with lattice constants a = 3.1423(2) Å (resp. 3.1502(3) Å) and c = 3.5084(3) Å (resp. 3.5041(3) Å) for crystals grown under Sc-rich (resp. B-rich) conditions. Crystals natively grow along the in-plane [100] direction. Electron backscattered diffraction shows that Sc-flux growth results in boules with multiple domains containing Sc inclusions, with the domains highly aligned. In contrast, B-flux boules are single domain after the initial nucleation region. Rocking-curve measurements of B-flux crystals for the (h000) and (000l) reflections show single peaks, establishing that the crystals are free from grain boundaries; the asymmetry in the scattered-intensity tails suggests the presence of point defects. Surface X-ray photoemission spectroscopy shows that the electronic environment in B-flux crystals is superior to that of Sc-flux crystals and produces highly resolved binding-energy peaks for B 1s and Sc 2p. Work-function measurements for the (11-20) plane give a value of approximately 5 eV, consistent with the highly electrically conductive nature of ScB2. These results demonstrate the viable ambient-pressure growth of ScB2, establish it as a lattice-matched substrate candidate for Al-rich AlGaN power microelectronics, and show that this growth route enables scalable manufacturing of ScB2 substrates.
ER -