Ferroelectric YAlN grown by molecular beam epitaxy
Ding Wang, Shubham Mondal, Jiangnan Liu, Mingtao Hu, Ping Wang, Samuel Yang, Danhao Wang, Yixin Xiao, Yuanpeng Wu, Tao Ma, Zetian Mi
Abstract
We report the demonstration of ferroelectric switching in yttrium (Y)-doped nitride semiconductors. In this study, single-crystalline, wurtzite Y0.07Al0.93N films were epitaxially grown on GaN/sapphire templates by plasma-assisted molecular beam epitaxy. The ferroelectric switching process has been investigated by current density–electric field (J-E) and polarization–electric field (P-E) loops as well as positive-up-negative-down measurements, showing a coercive field of ∼6 MV/cm and a switchable polarization of ∼130 μC/cm2. Ferroelectric switching was further confirmed via butterfly shape capacitance–voltage (C-V) loops and polarity-sensitive wet etching. The realization of ferroelectric, Y-doped AlN films further extends the family of nitride ferroelectrics and unravels a wealth of intriguing opportunities in III-nitride based electronic, piezo-electronic, and optoelectronic devices.