THE OPTICAL-PROPERTIES OF THE THIN CUINS2 AND IN-S LAYERS AIRLESS SPRAY

In this work we have studied the optical properties of the thin CuInS2 and In-S layers prepared by airless spray << P.S.A. >>. The study of the optical properties from the ellipsometric measure realized in the interval energy of incident photons [1.5-4] eV, has showed that the re fraction index n, and the extinction coefficient k, vary in the interv al [1.8-2.3] and 10.45-0.801 respectively. The absorption coefficient a of the thin CuInS2 layers realized for different ratios x of the con centrations in the spray solution (x = [CuI]/[InIII]) is high with val ues varied between (5 x 10(4) and 18 x 10(4) cm-1). The direct gap ene rgy of the thin CuInS2 layers of the order of 1.38 eV. In the same way , we study the spectrum variation of n1(lambda) and k1(lambda) of the thin In-S layers, realized for two values of ratio y of the concentrat ion in the spray solution (y = [In3+]/[s2-]). shows that for the value of y = 0.6 (material beta-In2S3) the refraction index is higher than that of the thin layer obtained for the value of y = 0.75 (material In 6S7) [1], and that the extinction coefficient is lower than that of In 6S7. For In-S thin layers, a is also high with values varing between 2 x 10(4) and 12 x 10(4) cm-1. The direct band gap of materials beta-In 2S3 and In6S7 are 2.22 eV and 1.94 eV respectively. The heat treatment under vacuum at 573 K during two hours improves the optical quality o f the thin << p >> type CuInS2 Layer.