Ultrathin films of p-sexiphenyl, formed by vapor-deposition onto KCl(001) substrates, have been investigated by x-ray diffraction (XRD) and atomic force microscopy (AFM). Analysis of the XRD data shows that the temperature of the alkali halide substrate during deposition affects the orientations of the molecules within the adsorbed films. AFM images contribute independent evidence consistent with the XRD results. The results are reproducible and suggest that ultrathin films of p-6P molecules can be grown with desired molecular orientations by carefully selecting the appropriate substrate temperature during deposition. (C) 2004 American Vacuum Society.