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 refraction index n, and the extinction coefficient k, vary in the interval [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 concentrations in the spray solution (x = [CuI]/[InIII]) is high with values varied between (5 x 10(4) and 18 x 10(4) cm-1). The direct gap energy 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 concentration 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 In6S7) [1], and that the extinction coefficient is lower than that of In6S7. 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-In2S3 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 of the thin << p >> type CuInS2 Layer.