Tek Katlı İnce Filmlerin Optik Özelliklerinin Swanepoel Modeli İle Belirlenmesi İçin Yazılım Geliştirilmesi

Abstract

The accuracy of the complex refractive index information of thin films due to the wavelength is very important both for researchers and technologically. This information includes information such as optical band (for semiconductors and insulators), defect levels, phonon and plasma frequencies. In addition, refractive index information is also needed for modeling and designing of optical devices such as solar panels, interference filters and display technologies, and for broadband / narrowband optical coatings and intelligent glasses. The optical constants of thin films can be calculated, the obtained data can be stored in a database and designs can be made using these data, while such importance is given in optical and surface technology based studies, the absence of a domestic computer program for the optical characterization of thin films in our country slows and foreign-dependent the work of researchers and engineers working in this area. For this purpose, as the first step in developing a program with the optical characterization and modeling capabilities of thin films, the OPth program was developed to calculate the optical constants and thicknesses of thin films from the optical transmittance data obtained in the ultraviolet – visible - near infrared region of the electromagnetic spectrum, based on the Swanepoel envelope method. The envelope method uses only the envelope curve drawn from the maximum and minimum points of the interference fringes using the optical transmission spectrum of the beam perpendicular to the surface, and obtains the refractive index and absorption coefficient of the single-layer thin film with high accuracy, which is coated on a semi-infinite or specific substrate. This method is only applicable to the weak absorption region where the extinction coefficient is very small and is suitable for refractive index of thin film is different from the substrate. Swanepoel has also taken into consideration the contributions of multiple reflections from the bottom surface of the substrate and substrate size. Current commercial software has some disadvantages, such as the user interface and the complexity of the data input and output. The OPth program has been developed both for these problems and for faster and more efficient operation. A lot of thin film transmittance data were used for the purpose of testing the developed OPth program, but optical transmittance measurements of ZnS and Ta2O5 thin films and glass substrate such as BK7 were used for literature comparison. The output of the OPth program will have a complex refractive index, absorption coefficient, thickness and optical band gap of the thin films.