| Abstract
| - Scanning tunneling microscopy was used to study the morphological behavior of 1−2 monolayers (ML) of5,6,11,12,17,18-hexaazatrinaphthylene (HATNA) deposited on Au(111). The first ML consisted of moleculesflat on the surface, arranged in one of three different ordered phases depending on annealing parameters. Thesecond ML assumed an upright orientation and tended to order only if the first layer was disordered. Scanningtunneling spectroscopy of 1−2 ML ordered HATNA was compared to ultraviolet photoemission spectroscopyand inverse photoemission spectroscopy of 80 Å amorphous HATNA. There is good agreement betweentechniques in the transport band gap (∼3.80 eV), but the position of the Fermi level in the gap is shifted inthe tunneling spectra by about 0.75 eV toward the highest occupied molecular orbital. The shift may be dueto morphological effects or degradation from ultraviolet light irradiation.
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