Secondary ion mass spectrometry study of Ti⁴⁺diffusion properties in congruent Er:LiNbO₃codoped with moderate concentration of MgO

Abstract

At 1100 C, the diffusion properties of Ti 4+ into congruent LiNbO 3 crystals codoped with 0.5 mol% Er 2 O 3 and different MgO concentrations of 0.5, 1.0, and 1.5 mol% have been studied by secondary ion mass spectrometry (SIMS). Three Y-cut and three Z-cut plates with different Mg doping levels were coated with a 60-nm-thick Ti film at first and then annealed at 1100 C for 28 h in a wet O 2 atmosphere. SIMS was used to analyze depth profile characteristics of diffused Ti ions and the constituent elements of the substrate as well. The results show that the diffusion reservoir was exhausted and the Ti metal film was completely diffused. All measured Ti profiles follow a Gaussian function. No Mg out-diffusion accompanied the Ti in-diffusion procedure for all crystals studied. The 1/e diffusion depth is similar to 8.3/10.2, 7.4/8.7, and 6.6/8.2 AE 0.2/0.2 mm/mm for the Y/Zcut crystal with the Mg doping level of 0.5, 1.0, and 1.5 mol%, respectively, yielding a Ti 4+ diffusivity of 0.62/0.93, 0.49/0.67, and 0.39/0.60 AE 0.03/0.03 (mm 2 /h)/(mm 2 /h), respectively. The diffusion shows definite anisotropy and a considerable MgO doping level effect. Under the same Mg doping level, the diffusion in a Z-cut crystal is faster. The diffusivity decreases with the increase of the Mg doping level. This effect is qualitatively explained from the viewpoint of the Mg doping effect on concentration of the intrinsic defects in LiNbO 3 crystal.

Concentration Determination of Er3+ in LiNbO3 Crystal by Absorption Spectroscopy

“…Over the past years, a family of Ti-or vapor Zn-diffused Er:LiNbO 3 waveguide lasers (amplifiers) and integrated devices have been demonstrated. [1][2][3][4][5][6][7][8] For purposes of suppressing the photorefractive effect, some other ions (named D n1 ) such as Mg 21 ,[9][10][11][12][13][14][15][16] Zn 21 , 17 Sc 31 , 18 In 31 , 19 and Hf 4120 are codoped into an Er:LiNbO 3 crystal. For purposes of increasing the pumping absorption at 0.98 mm wavelength and hence improving the pump efficiency, some Yb 31 ions are codoped.…”