Starting with the data for the sample prepared with a substrate temperature of 350 K (Fig. 4, bottom), three features are visible at q z positions of ∼0.5, 1.0 and 2.0 Å–1. These peak positions are in good agreement with the peaks observed in the specular diffraction data presented in Fig. 2 (peaks would intercept the q z axis at ∼0.51, 1.01 and 2.02 Å–1). These features extend along Debye–Scherrer rings (rings along a constant q value), showing that while there is a preferred orientation of the molecules on the surface, there is also mosaicity present and the texture is not highly defined. The first two stronger features at lower q correspond to approximately upright-standing molecules, while the weaker feature at ∼2.0 Å–1 corresponds to molecules lying on the substrate surface. A vertical feature resembling a rod smeared along a Debye–Scherrer ring is observed at q xy ≈ 1.88 Å–1, which corresponds to a d-spacing of 3.34 Å. This distance agrees well with the length typically associated with intermolecular π–π interactions and is in agreement with the observation of primarily standing molecules, as it is observed in the in-plane direction. The fact that no sharp Bragg peaks are observed, coupled with the presence of a rod-like feature in the in-plane direction points to a disordered layered structure: the film is partially ordered into layers perpendicular to the substrate surface, but there is no inter-layer ordering present as would be observed for a three-dimensionally ordered crystal.