提升波導型熱輻射紅外線發射器發光效率並應用於二氧化碳氣體偵測

Abstract

本文針對二氧化碳氣體於紅外線波段吸收與增加波導型紅外線熱輻射發射器發射效率之研究。經由量測得知二氧化碳氣體之紅外線吸收波長位於2.7微與4.26微米，並精準的定義波導型紅外線熱輻射發射器與氧化層厚度的關係，製造出針對二氧化碳吸收波長於4.26微米的紅外線光源。並且發現加熱電極之圖形顯著地影響波導型紅外線熱輻射發射器發射效率，透過蜿蜒的圖形使電流與熱流集中於圖形轉角處使之產生更多熱源進而造成熱源的溫度更均勻。並藉由提高加熱電極的長寬比與加熱面積，有效的提升熱電轉換效率。根據經由量測獲得二氧化碳氣體位於4.26微米之吸收係數介於0.32~0.33 cm-1之間，進而架設非分光紅外線氣體偵測系統以獲取二氧化碳濃度之資訊。

This thesis focuses on the absorption of CO2 in infrared region and improving the emission efficiency of waveguide thermal emitter. The absorption wavelengths of CO2 at 2.7 μm and 4.26 μm have been discovered. And relation between the emission wavelength of WTE and thickness of oxide layer is precisely defined. The emission efficiency of infrared thermal is affected significantly by geometry of electrode. The winding current path will cause current and the heat flux accumulates at the corner of the pattern to generate more heat source and result in more uniform temperature in the heat source. And the higher L/W ratio causes the higher conversion efficiency, and larger area will cause more heat source. Base on the absorption coefficient of CO2 in 4.26 μm measured to be about 0.32~0.33 cm-1, a NDIR system to measure the concentration of CO2 is built.