Optical Parameter Analysis of Thin Absorbing Films Measured by the Photovoltage Method |
| R. Pavelka, J. Hlávka, I. Ohlídal Department of Solid State Physics, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic and H. Sitter J. Kepler University, Institute of Experimental Physics, 4040 Linz, Austria |
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| A special method for measuring the optical parameters of thin absorbing films is presented. Within the method the radiation transmitted through the layer is measured. The transmitted radiation is detected by the space charge region which is located in the substrate at the interface with the layer. The space charge region acts as a photodetector placed just behind the layer. In this paper the method is applied to characterize a system of an absorbing ZnSe film on a GaAs substrate. The values of the optical parameters of the film are evaluated. This means that the value of the thickness and the spectral dependences of both the refractive index and extinction coefficient are determined. The spectral dependences of both optical constants are determined in the visible range. Finally, the comparison of our results obtained by this method with the results obtained from ellipsometric and reflectance measurements is presented. |
| DOI: 10.12693/APhysPolA.94.468 PACS numbers: 78.20.Ci, 72.40.+w |