| Tez Türü | Doktora |
| Ülke | Amerika Birleşik Devletleri |
| Kurum/Üniversite | University of California, Davis |
| Enstitü | Mühendislik Fakültesi |
| Anabilimdalı | Elektrik ve Bilgisayar Mühendisliği |
| Tez Onay Yılı | 2018 |
| Öğrenci Adı ve Soyadı | Muhammed TAN |
| Tez Danışmanı | Prof. Charles E. Hunt |
| İlgilizce Özet | Optically transparent and electrically conductive materials are unique in that they possess two opposing properties and they are vital in optoelectronics applications where light is either emitted or absorbed passing through such layers that transport electrons. In this work, Fluorine-doped tin oxide thin films are grown on flat and curved glass substrates via spray pyrolysis, an inexpensive and versatile thin film growth method. The main target application for this study is the use of a sustainable and transparent conductive electrode (anode) in field emission lighting; the advantage of using a transparent anode layer for this application is briefly discussed. The proposed use of a thermally conductive anode like F-doped tin oxide as an effective thermal bridge between the poorly conducting cathodoluminescent phosphors and the glass envelope of field emission lamps would alleviate heating in the phosphors and enhance the luminous efficacy of radiation of field emission lamps. Sustainability is also of importance in transparent conductors due to the scarcity of Indium used in most common transparent conductive material, Tin-doped Indium Oxide aka ITO or Indium Tin Oxide. Tin oxide stands out as the lowest cost candidate that also has a comparably good chemical and thermal stability. In addition, it is also vacuum-compatible; important because field emission lamps require high-vacuum to operate. Precursor solutions of 0.2 M SnCl4· 5H2O in methanol contained varying F-dopant level; obtained by varying the NH4F content in terms of atomic F/Sn ratio in the solution from 75%, 150% to 200%. The substrate surface temperature ranged from 300 °C, 350 °C to 400 °C effecting the electrical sheet resistance and optical transmittance of the grown F-doped tin oxide thin films. Four-point probe sheet resistance measurements, Hall effect studies, visible optical transmittance spectrometry of the thin films are undertaken to observe the electrical and optical properties, and the thin film thickness. Electrical sheet resistance values down to 4.3 Ω/square and oscillating optical transmittance patterns (>85%) are obtained for F-doped tin oxide films grown on flat glass substrates. Haacke's figure of merit for transparent conductors and thin film growth rates are shown for the studied flat-substrate samples. Thickness control of the thin films was attained by altering the volume of the precursor solution while keeping the molarity constant. Finally, the applicability of the spray pyrolysis thin film growth method on curved glass substrates is demonstrated using constant-radius watch glasses and bulb hemispheres as a basis for commercial outlook. |
