J. Mater. Sci. Technol. ›› 2023, Vol. 160: 139-147.DOI: 10.1016/j.jmst.2023.03.030

• Research Article • Previous Articles     Next Articles

Single crystal-single crystal bonding of langasite exhibited high strength of 23.28 MPa

Guangyao Peia, Binghe Maa,*, Tao Yea,*, Zhonggang Zhanga, Keli Zhaoa, Jinjun Denga, Seeram Ramakrishnab, Jian Luoa,*   

  1. aMinistry of Education Key Laboratory of Micro/Nano Systems for Aerospace, Northwestern Polytechnical University, Xi’an 710072, China;
    bCentre for Nanofibers and Nanotechnology, National University of Singapore, 117576, Singapore
  • Received:2022-12-21 Revised:2023-02-21 Accepted:2023-03-18 Published:2023-10-10 Online:2023-04-25
  • Contact: *E-mail addresses: . mabh@nwpu.edu.cn (B. Ma), yetao@nwpu.edu.cn (T. Ye), jian.luo@nwpu.edu.cn (J. Luo)

Abstract: Langasite (LGS, La3Ga5SiO14) is a promising material in high-temperature piezoelectric devices due to its excellent thermal stability, piezoelectricity, and electrical property. A major challenge in the development of LGS-based devices is to form high-strength bonding of the brittle LGS. Here, we report that the single crystal-single crystal (dual-SC) bonding of LGS is realized through thermal activation under a low compression of 50 kPa for the first time. A record bonding strength of 23.28 MPa is achieved within the dual-SC bonded LGS/LGS structure (with a high bonding ratio exceeding 93%), which is 5 times higher than that of the recent reported LGS/LGS bonding structure (in which a relatively fragile amorphous interface layer is formed between the two LGS samples). The smooth and void-free dual-SC bonding interface of LGS is verified via the cross-sectional transmission electron microscopy (TEM) observations.

Key words: Thermal activation, Single crystal-single crystal bonding, Langasite, High-strength, Low compression