Early Stage Growth Process of Dinaphtho[2,3‐b:2',3'‐f]thieno[3,2‐b]thiophene (DNTT) Thin Film

The early stage growth of dinaphtho[2,3‐b:2',3'‐f]thieno[3,2‐b]thiophenes (DNTTs) thin films are investigated using grazing incidence X‐ray diffraction (GIXD) and surface morphology analysis using atomic force microscopy (AFM). The thin‐film growth conditions are controlled using a slow deposition method. The vertical orientation of DNTT is confirmed from the growth of the first layer using GIXD. The morphologies of the first‐layer grains are universal in the growth rate range of 0.155–0.017 ML min−1. In addition, the dependence of the nuclei density on the deposition flow rate indicates that two molecules (dimers) are required for nucleation. This result suggests that fewer molecules are sufficient for nucleation in the case of DNTT compared to pentacene thin film growth on SiO2. The early stage growth process of the DNTT thin film is investigated using 2D‐GIXD and surface morphology analyses using AFM. Detailed AFM analysis reveals that the minimum number for nucleation is two molecules, based on the dependence of the nuclei density on the deposition flow rate. This value differs from other organic semiconductors, such as pentacene and 6T.