Ultrawide bandgap (UWBG) semiconductors exhibit exceptional electrical and thermal properties, offering strong potential for high power and high frequency electronics. However, efficient doping in UWBG materials is typically limited to either n type or p type, constraining their application to unipolar devices. The realization of pn junctions through heterogeneous integration of complementary UWBG or WBG semiconductors is hindered by lattice mismatch and thermal expansion differences. Here, we report the preliminary demonstration of diamond GaN heterojunction pn diodes fabricated via grafting. A single crystalline p plus diamond nanomembrane was integrated onto an epitaxially grown c plane n plus GaN substrate with an ultrathin ALD Al2O3 interlayer. The resulting diodes exhibit an ideality factor of 1.55 and a rectification ratio of over 1e4. Structural and interfacial properties were examined by AFM, XRD, Raman, and STEM, providing critical insights to guide further optimization of diamond GaN pn heterojunction devices.
@article{arxiv.2510.25028,
title = {Preliminary Demonstration of Diamond-GaN pn Diodes via Grafting},
author = {Jie Zhou and Yi Lu and Chenyu Wang and Luke Suter and Aaron Hardy and Tien Khee Ng and Kai Sun and Yifu Guo and Yang Liu and Tsung-Han Tsai and Xuanyu Zhou and Connor S Bailey and Michael Eller and Stephanie Liu and Zetian Mi and Boon S. Ooi and Matthias Muehle and Katherine Fountaine and Vincent Gambin and Jung-Hun Seo and Zhenqiang Ma},
journal= {arXiv preprint arXiv:2510.25028},
year = {2025}
}