High quality ZnO layers with adjustable refractive indices for integrated optics applications
1995; Elsevier BV; Volume: 4; Issue: 6 Linguagem: Inglês
10.1016/0925-3467(95)00028-3
ISSN1873-1252
AutoresRené Heideman, Paul Lambeck, Han Gardeniers,
Tópico(s)Optical Coatings and Gratings
ResumoThin (∼ 1 μm) crystalline ZnO films with a good optical quality and good (0002) texture are grown under two considerably different process parameter sets using a r.f. planar magnetron sputtering unit. The optical parameters of the two corresponding ZnO layers are distinctly different: high refractive index (≅ 2.0 at λ = 632.8 nm) ZnO films resembling the single crystal form, and ZnO films with considerably lower (typical difference 0.05) refractive indices. The refractive index of the latter ZnO layers is adjustable (∼ 1.93–1.96 at λ = 632.8 nm) through the process deposition parameters. It is shown that the difference in refractive index between the two ZnO types most probably results from a difference in package density of the crystal columns. The optical waveguide losses of both ZnO types are typically 1–3 dB/cm at λ = 632.8 nm, however the low refractive index ZnO layers need a post-deposition anneal step to obtain these values. The two ZnO types are used to fabricate optical channel-and slab waveguides with small refractive index differences.
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