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

• Main Authors: Wencan Li, Jiao Cui, Weiwei Wang, Dahuai Zheng, Longfei Jia, Shahzad Saeed, Hongde Liu, Romano Rupp, Yongfa Kong, Jingjun Xu
• Format: Article
• Language: English
• Published: MDPI AG 2019-03-01
• Series: Materials
• Subjects: lithium niobate film; pulsed laser deposition; nitrogen-doped; p-type conductivity
• Online Access: http://www.mdpi.com/1996-1944/12/5/819
• ISSN: 1996-1944

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.