Thin films of Cu(In,Ga)Se2 are grown by a co‐evaporation process in which the In, Ga, and Se fluxes, as well as the substrate temperature, are constant and the only variable is the Cu flux. This Cu flux varies in three steps in such a way that the growing film evolves from Cu‐poor to Cu‐rich and then back to Cu‐poor. The film growth is monitored by the ‘end point detection’ method, and film thicknesses of the order of 2 μm are deposited in less than 20 min. Quality devices (efficiencies above 15%) are produced in our baseline processes for all of the other synthesis steps. The Cu(In,Ga)Se2 layers are studied from a (112) versus (220) (204) orientation and recrystallization point of view. Including the results from a previous study on the influence of the substrate temperature to the present X‐ray diffraction and scanning as well as tunneling electron microscopy data, a five‐stage growth model for the films is described. The specific features of these films are that they are weakly (220) (204) oriented and exhibit crevices in their top fractions. The growth model hypothesizes about the origins of these crevices and on how to avoid them. Copyright © 2003 John Wiley & Sons, Ltd.

A CuInSe2 (CIS) bulk single crystal grown by the directional freezing method from the melt at 1250°C shows superior crystal quality, as evidenced by its (p-type) electrical properties. Photoluminescence at 1.5 K shows a strong and well resolved spectrum with fine structures never before observed from this compound. Free exciton emission exhibits a doublet structure which can either be described as a splitting due to the uniaxial crystal field or as a polariton. The energy gap of the CIS semiconductor as determined from the temperature dependence of the free exciton line is 1.058 eV. Two moderate free-to-bound transitions are assigned to VCu and CuIn acceptors. A weak PL peak corresponding to a deep level is interpreted as arising from the Sei acceptor. Strong phonon replicas are also observed for the first time in a CIS bulk single crystal. The phonon wavelength of 218–237 cm-1 is in good agreement with the reported Raman result of 233 cm-1 for the LO phonon.

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