Features of Bridgman-grown CuInSe2

Using a one-ampoule method, ingots of CuInSe2 were grown by the vertical Bridgman technique with specific nonstoichiometric proportions of the starting elements copper, indium and selenium. With stoichiometry or an excess of selenium, the ingots were p-type. With a deficiency of selenium, n-type conductivity was obtained but with binary phases present, such as InSe, in the last zone to freeze of the ingot. Ingots were also prepared with excess copper for melt compositions corresponding to CuxInSe2, where x was 1.1, 1.2 and 1.3. In the last zone to freeze of all these p-type ingots, precipitation occurred of copper containing dissolved selenium or indium. In the precipitate-free main part of these copper-excess ingots, no change of electrical resistivity was observed with increased copper content. However, in regions of the chalcopyrite adjacent to precipitated copper areas, at the end of each ingot, the resistivity was apparently increased. (C) 2003 Elsevier Science B.V. All rights reserved.