Economical construction of spin coater for the fabrication of dielectric reflectors

Abstract

Spin-coating is a versatile technique that utilizes only a few drops of the synthesized gel as an empirical method to fabricate the appropriate thin films. However, the economical design of a spin coater is always ground-breaking research. This paper reports the development of a spin coater using low-cost components such as SMPS, a brushless D.C. motor, and a proximity sensor. All of these components were contained in a stainless-steel unit and the entire equipment cost only 63 dollars, making it significantly less expensive than a standard one. The constructed spin coater was tested by fabricating three-and-five multilayer structures of TiO2/SiO2 with their respective sol–gel synthesized gels, and an X-ray diffraction (XRD) studies on the structures revealed a broad peak at 25°, confirming the existence of anatase TiO2 (titania) phase and non-crystalline amorphous phase of SiO2 (silica). Fourier transform infrared (FT-IR) spectroscopy endorsed the presence of titania and silica functional linkages by revealing vibrational bonds at 736 and 612 cm−1, respectively. Field emission scanning electron microscopy (FESEM) in cross-sectional mode on the three- and five-multilayer titania and silica structures evidenced the presence of titania and silica layers with intense (bright) and gloomy (dark) nature respectively. Finally, the reflectance study of the multilayer structures utilising ultraviolet–visible and near-infrared (UV–vis-NIR) spectroscopic showed 68 % and 100 % reflectance in the near-infrared region respectively, and demonstrated to be a dielectric reflector.