2016 年 67 巻 7 号 p. 370-374
Cyclic durability of adsorption-induced electrochromic（AiEC）color change was investigated for a microvillus-structured indium-nitride （InN）film fabricated by reactive evaporation with a glancing-angle scheme. Cross-sectional observation revealed that the InN film has a microvillus-like nanostructure with column diameter of approx. 200 nm and gap width of approx. 20 nm. The InN film exhibited AiEC behavior in the visible-infrared range with the maximum transmittance change of 58% at 680 nm wavelength. The AiEC lifespan of the microvillus-structured InN film was 2.1×104 cycles with polarization voltages of －1.4 V（cathodic）and ＋0.2 V（anodic）. The InN film degradation was found to occur because of irreversible transformation of InN into indium hydroxide. This reaction was presumed to be induced by permanent bond formation between surface indium atoms and -OH at anodic polarization. Surface area expansion by introduction of the microvillus-like structure provokes not only an improvement of transmittance change, but also rapid degradation of InN.
