• 한국군사과학기술학회지
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• 제17권5호
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• pp.672-679
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• 2014

To improve sensing capability of infrared, heat-resistance and mechanical properties, the $SiO_2$ and $TiO_2$ anti-reflective layers were coated on sapphire substrate by MOCVD. The standard wavelength was 4,600nm, and the thickness of anti-reflective layers were 379 and 758nm in case of ${\lambda}/4$ and ${\lambda}/2$ of incident angle($65^{\circ}$), respectively. The $SiO_2$ and $TiO_2$ anti-reflective layers were coated 12.6 and 9.7nm/min of deposition rates by increasing oxygen pressure to set the ideal refractive index of 1.283. In case of $SiO_2({\lambda}/2)$ coating, the transmittance increased from 55.0 to 62.7%. The transmittance of $TiO_2({\lambda}/2)$ anti-reflective layer also increased from 55.0 to 64.8%. The flexural strength of $SiO_2({\lambda}/2)$ and $TiO_2({\lambda}/2)$ layer coated sapphire increased from 337.8 to 362.9 and 371.8MPa, respectively. The flexural strength at $500^{\circ}C$ of these materials also increased respectively to 304.5, 358.2MPa from 265.9MPa. From these results, we confirmed these materials can be used as transmission window of infrared light.