Effects of Substrate Temperature on Nanomechanical Properties of Pulsed Laser Deposited Bi2Te3 Films

Coatings

I-Ju Teng¹  Le Thi Cam Tuyen²  Jenh-Yih Juang³  Yu-Chen Chung⁴  Sheng-Rui Jian⁴  Hui-Ping Cheng⁴  Phuoc Huu Le⁵  Chih-Ming Lin⁶ 

[1] College of Engineering, National Taiwan University of Science and Technology, Taipei 106335, Taiwan;Department of Chemical Engineering, College of Engineering Technology, Can Tho University, 3/2 Street, Can Tho City 900000, Vietnam;Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan;Department of Materials Science and Engineering, I-Shou University, Kaohsiung 84001, Taiwan;Department of Physics and Biophysics, Faculty of Basic Sciences, Can Tho University of Medicine and Pharmacy, Can Tho City 94000, Vietnam;Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan;

关键词: Bi₂Te₃ thin films;    XRD;    SEM;    nanoindentation;    pop-in;    hardness;   

DOI  :  10.3390/coatings12060871

来源: DOAJ

【 摘 要 】

The correlations among microstructure, surface morphology, hardness, and elastic modulus of Bi₂Te₃ thin films deposited on c-plane sapphire substrates by pulsed laser deposition are investigated. X-ray diffraction (XRD) and transmission electron microscopy are used to characterize the microstructures of the Bi₂Te₃ thin films. The XRD analyses revealed that the Bi₂Te₃ thin films were highly (00l)-oriented and exhibited progressively improved crystallinity when the substrate temperature (T_S) increased. The hardness and elastic modulus of the Bi₂Te₃ thin films determined by nanoindentation operated with the continuous contact stiffness measurement (CSM) mode are both substantially larger than those reported for bulk samples, albeit both decrease monotonically with increasing crystallite size and follow the Hall—Petch relation closely. Moreover, the Berkovich nanoindentation-induced crack exhibited trans-granular cracking behaviors for all films investigated. The fracture toughness was significantly higher for films deposited at the lower T_S; meanwhile, the fracture energy was almost the same when the crystallite size was suppressed, which indicated a prominent role of grain boundary in governing the deformation characteristics of the present Bi₂Te₃ films.

【 授权许可】

Unknown