Preparation and passivation of GaAs(001) surfaces for growing organic molecules

• Published in: Nanotechnology Vol. 13; no. 3; pp. 352 - 356
• Main Authors: Nicoara, N, Cerrillo, I, Xueming, D, García, J M, García, B, Gómez-Navarro, C, Méndez, J, Baró, A M
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Bristol IOP Publishing 01.06.2002; Institute of Physics
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Molecular, atomic, ion, and chemical beam epitaxy; Passivation; Physics; Surface treatments; Organic dianhydride; Atomic force microscopy; Gallium arsenides; Epitaxial layers; Polycyclic compound; Surface treatments; Crystal growth from vapors; Chemical etching; Experimental study; MOCVD; STM; Substrates; Thin films; Heterocyclic oxygen compounds; Molecular beam epitaxy; LEED; Pretreatment; Comparative study; Organic compounds; Passivation
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/0957-4484/13/3/322

Growth of ordered organic films of 3, 4, 9, 10-perylene-tetracarboxylic-dianhydride (PTCDA), on inorganic substrates of GaAs(001) is investigated by means of low-energy electron diffraction, STM, and AFM. The passivation of the sample can be achieved by exposing the substrate to sulfur (the SnS2 compound) or wet-chemical etching using an S-containing etchant ($2C12). The sulfur-treated surfaces are less reactive and are suitable as substrates for the growth of epitaxial films. We have compared the growth of organic molecules on substrates prepared by two different methods. The samples prepared by MBE present smoother surfaces compared with chemically treated samples. Therefore, an improvement of the PTCDA molecular order is observed for the MBE samples, which exhibit the formation of crystals. (Author)