标题：Formation of optical barriers with excellent thermal stability in single-crystal sapphire by hydrogen ion implantation and thermal annealing
作者：William T. Spratt;Mengbing Huang;Chuanlei Jia;Lei Wang;Vimal K. Kamineni;Alain C. Diebold;Hua Xia
作者机构：College of Nanoscale Science and Engineering, University at Albany-SUNY, Albany, New York 12203, USA;College of Nanoscale Scienc
来源：Applied physics letters
摘要：We report a study on the use of hydrogen ion implantation to form optical barriers with excellent thermal stability in single-crystal sapphire. Sapphire crystals are implanted with H ions of energies 0.2-1 MeV to doses 10~(16)-10~(17) cm~(-2), followed by thermal annealing between 600-1200 deg C. Prism coupling experiments and spectroscopic ellipsometry indicate the formation of an optical barrier with decreased refractive index around the projected range of H ions in sapphire. The refractive index reduction is found to increase with annealing temperatures, reaching a maximum of approx3.2percent following annealing at 1200 deg C. The correlation of the structural properties with the formation of optical barriers and their thermal stability in sapphire crystals, is duscussed.