Design, fabrication and characterization of an ultra-broadband metamaterial absorber using bismuth in the near infrared region

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Elektrik ve Elektronik Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2018

Öğrenci: İMRE ÖZBAY

Danışman: GÖNÜL SAYAN

Özet:

In this study, the design-fabrication-characterization cycle of an ultra-broadband metamaterial absorber structure operating in the near infrared (NIR) is presented. The area of plasmonic metamaterial based broadband and ultra-broadband absorbers has been commenced less than ten years ago and such absorbers have quickly found applications in many areas including light harvesting, sensing, infrared imaging and very recently plasmonic hot electron mediated photochemistry. In this thesis, an ultrabroadband bismuth based metal-insulator-metal cavity absorber operating in the near infrared regime is presented. This is done together with a comprehensive literature review in conjunction with the relevance of the current work in literature. The device is composed of three layers (excluding the substrate that provides mechanical support) and the only layer requiring periodic lithographical patterning is the top layer which is patterned into nanodisks. Fourier Transform Infrared Spectroscopy (FTIR) measurements yield an absorption band of 800 nm -2400 nm. This makes the device suitable for microbolometer based infrared detection applications in most of the short wavelength infrared band (SWIR). The selection of materials and persistent optimization has lead to record breaking upper absorption edge to lower absoption edge ratio of 3:1 and a record breaking upper absorption wavelength edge to device thickness ratio of 10. Through using different techniques such as using multiple patterning, the results and the operation bandwidth can be further improved.