Analysis of hydrogen diffusion from proton-exchanged layers in LiNbO3

Hydrogen profiles for proton-exchanged layers in Z-cut LiNbO3 were obtained by secondary ion mass spectrometry measurements after annealing at 400 °C for times from 6 to 180 min. To fit the measured hydrogen profiles, it was necessary to use two separate Gaussian diffusion profiles which could be designated as a more slowly diffusing substitutional hydrogen on lithium sites and a more rapidly diffusing interstitial hydrogen. At 400 °C, analysis leads to a substitutional hydrogen diffusion coefficient Ds≊4.6×10−12 cm2/s and an interstitial hydrogen diffusion coefficient Di≊1.5×10−11 cm2/s.