Go Beyond Boron Nitride: Ternary Alloy and Bipolar Doping
Duanjun Cai
Xiamen University – Xiamen, China
_______________________________________
Hexagonal boron nitride (h-BN) has attacted broad research interests due to its ultrawide bandgap and unique optoeletronic and electrical properties. However, most studies mainly focused on synthesis, fundamentals, and applications on binary h-BN itself. As a growing community, the members in this family of BN should be extended towards broader bandgap rangs with, e.g., ternary or quaternary alloies aiming for potential optoelectronic applications. On the other hand, the impurity doping schemes are also important for more efficient bipolar conductive layers and photon emitters. Here, we summarize our recent work on 2D BGaN compounds, bipolar doping of h-BN film, and novel devices with h-BN bridging layer.
1) BGaN. we first conducted simulations on BGaN ternary alloy model using first principles calculations, revealing that the modulation of the Ga composition can regulate the BGaN alloy semiconductor bandgap in a range from 213 nm to 341 nm. Using a low-pressure chemical vapor deposition (LPCVD) method, we achieved 2D monolayer BGaN ternary alloy film with a maximum Ga composition up to 11%. This adjustable bandgap in BGaN will provide new potential in future optoelectronic devices.
2) By orbital engineering, both p– and n-type conductivities in h-BN monolayer have been obtained for the first time. The efficient p-type conduction in h-BN was obtained via Mg s-orbital modulated doping and Ge-O orbital coupling was proposed to achive n-type conductivity (100 nA). Moreover, a liquid phase growth of h-BN with simultaneous O doping further improved the n-type conductivity up to 169 nA.
3) Bidirectional Li-Fi LED mediated with h-BN monolayer. Sandwithed with Cu@hBN nanowires and GaN:Mg, a novel monolithic Li-Fi LED achieves natural white light emission and light communication at the same time.
References:
[1] G. Liu, Y. Tang, A. M. Soomro, D. J. Cai et al., Nano Energy 109, 108265 (2023).
[2] S. Lu, P. Shen, D. J. Cai et al., Nature communications 13, 3109 (2022).
[3] P. Shen, M. Yang, D. J. Cai et al., Applied Physics Letters, to be published (2025)
[4] G. Liu, H. Chen, D. J. Cai et al., Small, 2200563 (2022).
Email: dcai@xmu.edu.cn