Epitaxial growth of chloroaluminum and vanadyl phthalocyanine films on alkali halide single crystals by the molecular-beam-epitaxy technique

Abstract

Epitaxial chloroaluminum and vanadyl phthalocyanine (AlPcCl and VOPc) films have been prepared on alkali halide (100) surfaces by the molecular-beam-epitaxy technique. Their structures have been studied by scanning electron microscopy and transmission electron microscopy. The films consist of densely packed crystallites and seem to be continuous. The predominant phase of AlPcCl/NaCl is newly found bidirectionally oriented tetragonal, NaCl(100)(√13×√13)R±11°-AlPcCl. The phase of AlPcCl/KCl and AlPcCl/KBr is bidirectionally oriented tetragonal, KCl(100)(√10×√10)R±27°-AlPcCl and KBr(100)(√10×√10)R±27°-AlPcCl, respectively. The predominant phase of AlPcCl/KI is unidirectionally oriented tetragonal, KI(100)(3×3)R45°-AlPcCl. The phase of VOPc/KCl is bidirectionally oriented tetragonal, KCl(100)(√10×√10)R±27°-VOPc, while that of VOPc/KBr is unidirectionally oriented tetragonal, KBr(100)(3×3)R45°-VOPc. The preferential epitaxial lattice orientation is discussed based on the degree of lattice matching between phthalocyanine and substrates.