GROWTH OF ALPHA-HEXATHIENYL BY A MICRO MELT TECHNIQUE

alpha-Hexathienyl is a most promising thin film transistor material. F or the first time crystals large enough (500 mu m) for single crystal X-ray determinations have been prepared. A 30 mg melt was contained in a small capillary which was cooled in a hot stage microscope modified so as to produce a temperature gradient of 1 degrees C/mm along the t ube. The sample was cooled from above the melting point (309 degrees C ) to 280 degrees C at a rate of 0.1 degrees C/min. Best crystals were obtained when the melt depth was small.