Achieving ultrahigh hole mobility in hydrogen-terminated diamond via boron nitride modifications

Wide-bandgap semiconductors with high carrier mobility are in great demand for high-power radio-frequency applications. In the past decades, extensive efforts have been devoted to investigating the carrier transport properties of hydrogen-terminated diamond (H-diamond), however, achieving its high hole mobility remains a challenge, thereby limiting the development of diamond electronic devices. Herein, we propose a novel strategy to increase the hole mobility of H-diamond by boron nitride (BN) clusters modifications. Amorphous BN clusters were deposited on high-quality H-diamond surfaces using magnetron sputtering. The modified H-diamond exhibits an ultrahigh hole mobility of 1100 cm2 V-1 s-1, over 10-fold higher than that of H-diamond prior to BN modification. Moreover, the BN-modified H-diamond also exhibits outstanding high-temperature tolerance and excellent thermal stability benefitting from the passivation effect of BN. At 380 K, it still maintains a hole mobility of 385 cm2 V-1 s-1. Even after annealing at 350 K for over 8 h, there are no noticeable variations in its carrier transport properties. The hole mobility enhancing mechanism and the factors influencing carrier transport properties of the BN-modified H-diamond are discussed using first principles calculations analysis. The developed BN-modified H-diamond opens up new possibilities for diamond-based radio-frequency electronic devices operating in challenging temperature environments.