As-grown CVD ZnO optical waveguides on sapphire

Abstract
Optical‐waveguide loss was measured in as‐grown single‐crystalline ZnO films which were chemical‐vapor‐deposited on intermediately sputter‐deposited very thin ZnO films on sapphire substrates. The obtained minimum attenuations at 6328 Å are 18.3, 14.2, 10.7, 8.7, 4.7, 2.4, 1.5, and 0.7 dB/cm for the seventh, sixth, fifth, fourth, third, second, first, and zeroth TE modes, respectively, in a 2.57‐μm‐thick ZnO film. A strip waveguide was made of the CVD ZnO film selectively grown on an intermediately sputter‐deposited ZnO pattern on sapphire.