GROWTH AND CHARACTERIZATION OF THERMALLY EVAPORATED ENERGY EFFICIENT COATINGS BASED ON THE TRANSITION METAL OXIDES (CHROMIUM OXIDE, NICKEL OXIDE, MOLYBDENUM OXIDE AND VANADIUM OXIDE). Masters thesis, King Fahd University of Petroleum and Minerals.
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Arabic Abstract
المرايا الشفافة العاكسة للحرارة هي طبقات تقوم بنفاذ الضوء بينما تعكس الحرارة في صورة الأشعة تحت الحمراء. في هذا البحث تم تحضير هذه المرايا كطبقتين: الأولى من الفضة و الثانية من أحد أكاسيد المعادن الانتقالية (أكاسيد المولبدينوم و الكروم و النيكل و الفاناديوم). الخصائص التركيبية تم دراستها بطريقة حيود الأشعة السينية ، و التي أوضحت أن طبقتي الفضة , أكسيد النيكل فقط تلبورتا. الخصائص الطوبوغرافية لأسطح الطبقات تم دراستها بالمجهر الذري ، و الذي أوضح أن أسطح الطبقات تكونت من تشكيل عمودي. الخصائص الكيميائية لأكاسيد المعادن وتوزع العناصر في الطبقات المرايا تم دراستها بمطيافية الإلكترونات، و التي أظهرت انتشار العناصر في جميع الطبقات. :ذلك تم دراسة الخصائص الضوئية لأكاسيد المعادن (معامل الانكسار و طاقة الفجوة) و للمرايا (النفاذ و الانعكاس) و التي أوضحت أن الطبقات المصنعة تميزت بنفاذية عالية للضوء و انكاس عالي للأشعة تحت الحمراء.
English Abstract
Transparent heat mirrors (THM) allow the visible range of electromagnetic radiation to transmit through them but reflect the infrared part. In order to realize this potential, the two layer dielectric/metal system was used on different types of substrates. The multilayer thin films were deposited on different substrates using different transitions metal oxides as the dielectrics. The selected metal oxides were chromium oxide (Cr2O3), molybdenum oxide (MoO3), nickel oxide (NiO), and vanadium oxide (V2O5) and were deposited by thermal evaporation. Silver (Ag) was used as metal. The surface morphology and structural properties were investigated by atomic force microscopy (AFM) and X-ray diffraction (XRD), respectively. XRD revealed that all the films were amorphous except nickel oxide. The AFM study revealed that the morphology of the surfaces exhibited a columnar structure. The root mean square surface roughness (Rrms) of the films indicated smooth surfaces of the metal oxides. The Rrms values for the silver films indicated a rough and porous structure. The chemical properties of the individual as well as the two layer structure films were determined using X-ray photoelectron spectroscopy (XPS). The depth profile of THM coatings showed that the interface between the two layers was not sharp, and thus diffusion of the oxide into the silver layer took place. The optical properties of the films such as band gap, absorption coefficient, refractive index, and extinction coefficient were determined from spectrophotometric measurements. The fabricated two layer structures were highly transparent in visible region and highly reflective in infrared region of electromagnetic spectrum, which exhibited the desired optical properties for transparent heat mirrors applications.
| Item Type: | Thesis (Masters) |
|---|---|
| Subjects: | Physics |
| Department: | College of Engineering and Physics > Physics |
| Committee Advisor: | Al-kuhaili, Mohammad Fayyad |
| Committee Members: | Faiz, Mohammad M. and Hamid, Anwar ul and Mekki, Abdel Karim |
| Depositing User: | SYED HASEEB ALI AHMAD (g201301070) |
| Date Deposited: | 07 Jun 2015 11:27 |
| Last Modified: | 01 Nov 2019 15:45 |
| URI: | http://eprints.kfupm.edu.sa/id/eprint/139541 |