Growth of Intrinsically Polar Crystalline Textures of Phosphangulene by Organic Molecular Beam Deposition

Under ambient conditions, materials belonging to polar space groups exceed charge compensation of intrinsically charged (hkl) faces. In the high vacuum, however, charge compensation becomes ineffective so that nucleating or growing polar crystalline materials on charged electrodes may lead to unipolar polycrystalline bulk materials (∞m texture). We present here a new approach to grow intrinsically polar organic crystalline textures by using an organic molecular beam deposition (OMBD) technique. Results indicate that the electrostatic polarity of the substrate influences substantially the formation of a phosphangulene polar organic texture. The influence of the electric field on the growth of crystals points to the fact that the electric field aligns developing crystals along the field, a property optimum for achieving a desired self-assembly being an intrinsically unipolar crystal texture for pyroelectric applications.