Charge Transfer at Hybrid Organic-Inorganic Interface

A. ur Rehmana, H.J. Zhangb, W. Pengc, A. Razaqd, K. Ibrahime, S.N. Baob aPhysics Department, University of Agriculture, Faisalabad 38040, Pakistan bPhysics Department, Zhejiang University, Hangzhou 310027, P.R. China cPhysics Department, Shandong University of Science and Technology, Shandong, 266510, P.R. China dPhysics Department, COMSATS Institute of Information Technology, Lahore, Pakistan eInstitute of High Energy Physics, Chinese Academy of Sciences, P.R. China

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Iron phthalocyanine molecule (FePc) thin films were deposited on Cu(100) and Si(100) substrates in sequential steps and the interface was characterized by means of scanning tunneling microscope, X-ray photoemission spectroscopy, and its sister technique ultra violet photoemission spectroscopy. At room temperature disordered structures are observed. However at elevated temperature ~480°, a long range ordered pattern is noticed indicating the increase of diffusion of adsorbed molecules on the substrate surface. All the photoemission spectra exhibited a clear change and shift in the adsorbed peaks. The change in binding energy of C 1s core level as revealed by X-ray photoemission spectroscopy is Vb=0.18 eV. Our calculated work function of the clean Si (100) surface is 4.09 eV. The hole and electron injection barriers are estimated as 1.22 eV and -1.38 eV, respectively. Based on the measured quantities, the interface dipole potential is found to be -0.04 eV. A minute charge transferred from each adsorbed molecule to the substrate is estimated as ca. 8.565 × 10-22 C. Besides, our computational density functional theory findings revealed a strong adsorbate-substrate interaction.

DOI:10.12693/APhysPolA.134.434 topics: FePc, Si (100), Cu(100), STM, PES, nanostructures, work function, charge density, interface dipole