| AVS 55th International Symposium & Exhibition | |
| Advanced Surface Engineering | Thursday Sessions |
| Session SE-ThP |
| Session: | Advanced Surface Engineering Poster Session |
| Presenter: | H. Takeuchi, Nagoya University, Japan |
| Authors: | H. Takaba, Nagoya University, Japan H. Takeuchi, Nagoya University, Japan Y. Inoue, Nagoya University, Japan O. Takai, Nagoya University, Japan |
| Correspondent: | Click to Email |
1. Introduction Electrochromic (EC) materials have a unique property of reversible color change with a burst of electrical charge. Much attention has been paid to the EC materials for application to “smart windows”, which control electrically the light and heat through the windows. We have investigated the EC properties of indium nitride (InN). The EC of InN is based on so-called Burstein-Moss shift induced by alternation of surface adsorbates. We have improved the EC properties of InN both by doping Ga to shift the color-change wavelength region and by introducing a biomimetic structural design in nano order to increase the EC amplitude. In this study, we deposit microvillus-structured InGaN films at some substrate temperatures and investigate the effect of deposition temperature on crystallinity, biomimetic structure and EC properties. 2. Experimental procedure The Ga-doped indium nitride (In1-xGaxN, 0≤x≤1) films were deposited in a vacuum evaporation system assisted with an active nitrogen source. Indium and gallium were deposited simultaneously from respective crucibles through a downstream of the nitrogen plasma generated from the active nitrogen source at the conditions of the nitrogen pressure of 0.04 Pa and the RF power of 300 W. The substrate holder was rotated at the speed of 10 rpm with the angle against the metal fluxes at 85° in order to synthesize the biomimetic microvillus-like nanostructures, and heated by lamp heater from behind. Crystallinity, microstructure and EC properties of the In1-xGaxN films were characterized by XRD, FE-SEM and UV-VIS spectrophotometry, respectively. 3. Result From XRD analysis, we confirmed that the In@1-x@Ga@x@N films prepared at high substrate temperature had higher crystallinity than at non-heated temperature. EC measurements showed that the EC amplitude of InGaN increased with the crystallinity improvement at high Ga composition. However, at low Ga composition, that of prepared at 150°C was larger than at 200°C because the effective surface area decreased due to microstructure evolution.