P-Type Lithium Niobate Thin Films Fabricated by Nitrogen-Doping

Nitrogen-doped lithium niobate (LiNbO₃:N) thin films were successfully fabricated on a Si-substrate using a nitrogen plasma beam supplied through a radio-frequency plasma apparatus as a dopant source via a pulsed laser deposition (PLD). The films were then characterized using X-Ray Diffraction (XRD) as polycrystalline with the predominant orientations of (012) and (104). The perfect surface appearance of the film was investigated by atomic force microscopy and Hall-effect measurements revealed a rare p-type conductivity in the LiNbO₃:N thin film. The hole concentration was 7.31 × 10¹⁵ cm^-3 with a field-effect mobility of 266 cm²V^-1s^-1. X-ray Photoelectron Spectroscopy (XPS) indicated that the atom content of nitrogen was 0.87%; N atoms were probably substituted for O sites, which contributed to the p-type conductivity. The realization of p-type LiNbO₃:N thin films grown on the Si substrate lead to improvements in the manufacturing of novel optoelectronic devices.