Influence of substrate temperature on the growth and optical waveguide properties of oriented LiNbO3 thin films

Effects of mechanical processing and annealing on optical coherence properties ofEr3+:LiNbO3 powders

“…This hypothesis is consistent with past observations of substantial lithium out-diffusion from the surface of bulk crystals when annealed in a wet oxygen atmosphere at temperatures above approximately 1100 C [56]. Moreover, changes in material properties due to lithium outdiffusion have been observed at temperatures as low as 600 C for LiNbO 3 thin films [50,51], suggesting that even lower annealing temperatures than used here may be optimal for micro/nano-powders. Finally, we examined powder #6 that was fabricated through in-diffusion of erbium into commercial LiNbO 3 powder.…”

“…Past studies have found that thin crystalline films of LiNbO 3 are particularly sensitive to high annealing temperatures [50,51], suggesting that similar effects might be observed for powders. Furthermore, while bulk crystals generally require reducing atmospheres [52] or vacuum [53] for significant oxygen to diffuse out of the crystal matrix during annealing, we found that in small crystallites the out diffusion occurs even when annealed in an ambient atmosphere, resulting in black powders.…”

“…The reference powder samples were mixed with ethanol to produce a slurry and then ground in a mill To investigate the effect of post fabrication thermal treatment, some powders were annealed in alumina crucibles in a tube furnace using a mullite tube providing peak temperatures of up to 1400 C. While thermal annealing can increase defect mobility and relieve crystal strain, LiNbO 3 can also be detrimentally affected by annealing at high temperatures due to the potential for outdiffusion of both lithium and oxygen, affecting the optical and electrical properties of the crystal. Past studies have found that thin crystalline films of LiNbO 3 are partic-ularly sensitive to high annealing temperatures [50,51], suggesting that similar effects might be observed for powders. Furthermore, while bulk crystals generally require reducing atmospheres [52] or vacuum [53] for significant oxygen to diffuse out of the crystal matrix during annealing, we found that in small crystallites the out diffusion occurs even when annealed in an ambient atmosphere, resulting in black powders.…”

Synthesis, microstructural and optical characterization of LiNbO3 thin films deposited by aerosol assisted chemical vapor deposition

“…Figure 5 (b) shows the magnitude of the ordinary refractive index, given by equation 1, of sample LNTFS-1 deposited onto silicon substrate plotted as a function of photon energy. It was observed that the magnitude of the refractive index (~1.995) of the sample LNTFS-1 was slightly lower than the value reported in the literature for thin films and bulk samples of LiNbO 3 at 633 nm wavelength corresponding to a photon energy of 1.96 eV (Kirkby & Florea, 2002;Takahashi et al, 2004;Wang et al, 2007). As shown in figure 5 (b), the refractive index of sample LNTFS-1 has the expected behavior showing a continuous increase as the photon energy increases.…”

“…Literature reports several deposition techniques of LiNbO 3 thin films employed as sol-gel (Kao et al, 2008;Nashimoto, Cima, McIntyre & Rhine, 1995;Takahashi et al, 2004;Terabe, Iyi, Kitamura & Kimura, 1995;Terabe, Kurashima, Gruverman, Matsui, Iyi & Kitamura, 1997), metalorganic chemical vapor deposition (MOCVD) (Akiyama, Shitanaka, Murakami, Shin, Yoshida & Imaishi, 2007;Lee & Feigelson, 1998), pulsed laser deposition (PLD) (Kilburger, Millon, Di Bin, Boulle, Guinebretière & Di Bin, 2010;Wang, Ye, Li & Zhao, 2007), radio-frequency magnetron sputtering (RFMS) (Bornand & Papet, 2003;Yilmaz, 2003), and ultrasonic spray pyrolysis (USP) process (Bornand et al, 2002;Bornand & Papet, 2003). The structural and morphological characterization of samples prepared, and requirements to obtain thin films of LiNbO 3 have been shown in those reports.…”