scholarly journals OPTICAL AND STRUCTURAL PROPERTIES OF OPTICAL THIN FILMS WITH VARIOUS COLUMNAR MICROSTRUCTURES

2017 ◽  
Vol 24 (1&2) ◽  
pp. 153-160
Author(s):  
Seouk-Hoon Woo ◽  
Yong Jun Park ◽  
Chang Kwon Hwangbo

In this study, optical and structural properties of the thin films prepared using glancing angle deposition (GLAD) are investigated. Various glancing angles and substrate rotations are employed to control the columnar microstructure of the films. The results show that as the glancing angle increases, the column angle and the porosity of TiO2 films increase and the refractive index decreases, due to shadow effects. The optical anisotropy of tilted and zigzag microstructure TiO2 films have a large anisotropy and reaches a maximum at a glancing angle of 60°, while that of helical microstructure TiO2 film deposited at 60° with substrate rotation shows a very small anisotropy due to the symmetric structure. It is found that the optical anisotropy of TiO2 films deposited by GLAD can be controlled by modification of microstructure.

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2413
Author(s):  
Yao Shan ◽  
Pian Liu ◽  
Yao Chen ◽  
Haotian Zhang ◽  
Huatian Tu ◽  
...  

Yttrium fluoride (YF3) columnar thin films (CTFs) were fabricated by electron beam evaporation with the glancing angle deposition method. The microstructures and optical properties of YF3 CTFs were studied systematically. The YF3 films grown at different deposition angles are all amorphous. As the deposition angle increases, the columns in YF3 CTFs become increasingly separated and inclined, and the volume fraction of YF3 decreases, resulting in lower refractive indices. This phenomenon is attributed to the self-shadowing effect and limited adatom diffusion. The YF3 CTFs are optically biaxial anisotropic with the long axis (c-axis) parallel to the columns, the short axis (b-axis) perpendicular to the columns, and the other axis (a-axis) parallel to the film interface. The principal refractive index along the b-axis for the 82°-deposited sample is approximately 1.233 at 550 nm. For the 78°-deposited sample, the differences of principal refractive indices between the c-axis and the b-axis and between the a-axis and the b-axis reach the maximum 0.056 and 0.029, respectively. The differences of principal refractive indices were affected by both the deposition angle and the volume fraction of YF3.


2015 ◽  
Vol 644 ◽  
pp. 65-69
Author(s):  
V. Madurga ◽  
C. Favieres ◽  
J. Vergara

Thin films of Co-Hf (≈ 86-14 % at.) were grown over Si micro-cantilevers using a glancing-angle deposition technique. A controlled easy direction of magnetisation (anisotropy field μoHk ≈ 0.1 T) in the longitudinal or in the transverse direction of the micro-cantilevers was generated. The mechanical properties of the films under the action of a magnetic field were opposite depending on the magnetisation’s easy direction: i) their deflection was either zero or the maximum value depending on the direction of the applied magnetic field with respect to the parallel or transverse easy direction of magnetisation; ii) the shift in the resonance frequency under a longitudinal or transverse magnetic field was also different depending on the longitudinal or transverse easy direction of magnetisation. The use of these coated devices with micromagnet-like films for sensors and transducers is discussed.


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