Boron nitride (BN) is an exceptional material and among its polymorphs, two-dimensional (2D) hexagonal and three-dimensional (3D) cubic BN (h-BN and c-BN) phases are most common. The phase stability regimes of these BN phases are still under debate and phase transformations of h-BN/c-BN remain a topic of interest. Here, we investigate the phase stability of 2D/3D h-BN/c-BN nanocomposites and show that the co-existence of two phases can lead to strong non-linear optical properties and low thermal conductivity at room temperature. Furthermore, spark-plasma sintering of the nanocomposite shows complete phase transformation to 2D h-BN with improved crystalline quality, where 3D c-BN grain sizes governs the nucleation and growth kinetics. Our demonstration might be insightful in phase engineering of BN polymorphs based nanocomposites with desirable properties for optoelectronics and thermal energy management applications.
@article{arxiv.2304.08474,
title = {Phase Stability of Hexagonal/cubic Boron Nitride Nanocomposites},
author = {Abhijit Biswas and Rui Xu and Joyce Christiansen-Salameh and Eugene Jeong and Gustavo A. Alvarez and Chenxi Li and Anand B. Puthirath and Bin Gao and Arushi Garg and Tia Gray and Harikishan Kannan and Xiang Zhang and Jacob Elkins and Tymofii S. Pieshkov and Robert Vajtai and A. Glen Birdwell and Mahesh R. Neupane and Bradford B. Pate and Tony Ivanov and Elias J. Garratt and Pengcheng Dai and Hanyu Zhu and Zhiting Tian and Pulickel M. Ajayan},
journal= {arXiv preprint arXiv:2304.08474},
year = {2023}
}