The film morphology is obviously dependent on the oblique angle. For the film deposited at 0°, i.e., vertically deposited, a dense and flat surface was obtained as shown in Figure 1a. When the deposition angle was ≥60°, porous nanostructure was formed as shown in Figure 1b,c,d,e. It has been ��-Nicotinamide datasheet illustrated that during the OAD process, self-shadowing effect and limited surface diffusion lead to the formation of distinct columnar structure [11, 15]. With the deposition angle further increased to 85°, an aligned self-standing TiN nanorod arrays with length of ca. 270 nm and diameter of ca. 90 nm was obtained, which can be seen from the side view image in Figure 1f.

Figure 1 Top view SEM images of TiN films deposited at various oblique angles. (a) 0°, (b) 60°, (c) 70°, (d) 80°, (e) 85°, and (f) side view image Cediranib order of (e). Insets show the side view images. Figure 2 displays the XRD patterns of the TiN films deposited at various incident angles. It can be seen that the TiN film deposited at 0° exhibits (111) HM781-36B supplier and (200) diffraction of the face-centered cubic (FCC) structure of TiN (JCPDS 38–1420). The (111) peak becomes weaker for the films deposited at ≥60°, which can be attributed to the decrease in film thickness [16] and the formation of nanostructure during the OAD process. Figure 2 XRD patterns of the TiN film deposited at various incident angles. The

refractive index (n e) of the as-prepared TiN films was measured by spectroscopic ellipsometry Carbohydrate at wavelengths from 500 to 900 nm. Figure 3a plots the refractive index of the TiN film as a function of the wavelength. One can see that the film refractive index diminishes with the increase of the deposition angle. For a clear demonstration, we plot the variation of n e at 600 nm as a function

of the deposition angle, which is illustrated in Figure 3b. As the deposition angle increases from 0° to 85°, n e decreases from 2.15 to 1.68, which is the result of the formation of nanostructure [17]. For two non-absorbing components with volume fractions f i and refractive indices n i, the Bruggemann effective medium approximation gives [18] Figure 3 The refractive index spectra and refractive index at a wavelength of the TiN films. (a) The refractive index spectra of the TiN films in the wavelength range of 500 to 900 nm. (b) The refractive index at a wavelength of 600 nm and the calculated porosity of the films, as a function of the oblique angle. Herein, n e of a porous film is given by an average of air and material when the pore size is much smaller than the wavelength. Using the n e at 600 nm, the porosity of the above TiN films is calculated using the Bruggemann approximation, and the result is displayed in Figure 3b. When the deposition angle is increased, the porosity increases and reaches the maximum at the deposition angle of 85°, which is in accordance with that observed by SEM (see Figure 1).