Electronic properties of the iron phthalocyanine thin films UHV annealed and exposed to oxygen

Szuber, J.; Szczepaniak, B.; Kochowski, S.; Opilski, A.

doi:10.1016/0042-207x(94)00127-8

Cited by 9 publications

(7 citation statements)

References 13 publications

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“…3(d). Four special points of curve in this figure – Φ Au , Φ CuPc , Φ FePc , and Φ Fe are typical characteristic work functions of the corresponding materials 37–39. From the fact that the work function curve between pristine CuPc and thick iron overlayer has some minimum we can suppose that, at low coverage of iron on the CuPc surface, the formation of some intermediate phase with work function Φ = 3.9 eV takes place, which is very close to the work function value Φ = 3.8 eV, measured for FePc thin films 28.…”

Section: Resultssupporting

confidence: 76%

Chemistry and electronic properties of ferromagnetic metal‐organic semiconductor interfaces: Fe on CuPc

Aristov

Молодцова

Ossipyan

et al. 2009

Physica Status Solidi (a)

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The chemistry and electronic properties of the interfaces formed between the ferromagnetic metal (Fe) and the model organic semiconductor copper phthalocyanine are investigated in ultra-high vacuum conditions for the case of metal deposition onto the organic molecular thin film. The studies were performed by means of core-level and valence-band high-resolution photoemission electron spectroscopy (PES) as well as near-edge X-ray absorption fine structure using synchrotron radiation. Metal overlayer formation on the top of the organic semiconductor was observed without substantial penetration of deposited metal species into the organic film. At the thin interface layer the ferromagnetic metal shows strong chemical interaction with the nitrogen and carbon of the organic films. Moreover, our results infer that, as a consequence of Fe deposition onto CuPc, central copper atoms of the organic molecules at the interface are reduced from Cu(II) to Cu(I), while Fe atoms are oxidized and/or the ferromagnetic metal replaces this central Cu atom. Further optimization of such an interface is thus required to allow and/or facilitate the injection of spin-polarized carriers into organic semiconductors

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Section: Resultssupporting

confidence: 76%

Chemistry and electronic properties of ferromagnetic metal‐organic semiconductor interfaces: Fe on CuPc

Aristov

Молодцова

Ossipyan

et al. 2009

Physica Status Solidi (a)

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“…To address this issue more directly, the results from once air exposed (Figures and ) and UHV only history samples (Figures −7) were compared. Since some of our data were acquired with no more than about 0.03 langmuir of total O 2 exposure, it seems very unlikely that every FePc would have an attached O 2 molecule yet we have never seen any high spots in either NiPc or CuPc samples.…”

Section: Resultsmentioning

confidence: 88%

“…Since some of our data were acquired with no more than about 0.03 langmuir of total O 2 exposure, it seems very unlikely that every FePc would have an attached O 2 molecule. 44 It should also be noted that CuPc and NiPc also are reported to adsorb oxygen with saturation coverage occurring at about 3 × 10 -8 Torr, 45 yet we have never seen any high spots in either NiPc or CuPc samples. Nevertheless, until an Auger or ESCA measurement can be made in the STM chamber before and after deposition and then after STM imaging, the issue cannot be totally closed.…”

Section: Resultsmentioning

confidence: 93%

Scanning Tunneling Microscopy of Metal Phthalocyanines: d⁶ and d⁸ Cases

1997

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Scanning tunneling microscopy (STM) images of iron(II) phthalocyanine (FePc) and nickel(II) phthalocyanine (NiPc) adsorbed on the Au(111) surface are reported. Both species provide images showing submolecular structure. A particularly exciting aspect of this work is the strong influence of the metal ion valence configuration on the observed tunneling images. Unlike NiPc, wherein the central metal appears as a hole in the molecular image, the iron ion in FePc is the highest point (about 0.25 nm) in the molecular image. These data are interpreted as indicating that the Fe(II) d 6 system has significant d orbital character near the Fermi energy while the Ni(II) d 8 system does not. This interpretation is consistent with theoretical calculations that predict a large contribution of iron d orbitals near the Fermi energy. The results reported here are also fully consistent with our previous report of CoPc and CuPc d orbital dependent images. An intriguing aspect of this work is that it may be possible to chemically identify different metal complexes simply by their appearance. Metal-organic complex systems of this type may also be viewed as single molecular electronic structures with different parts of the same molecule behaving as insulator, conductor, or semiconductor.

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“…A more evident influence of the oxygen adsorption on the work function c p as well as on the effective density of filled electronic band states N ( E ) localized in the band gap has previously been observed for the iron phthalocyanine (FePc) thin films [27]. Probably the mechanism of oxygen adsorption and the origin of the filled electronic states in both these phthalocyanine thin films are rather different.…”

Section: Resultsmentioning

confidence: 91%

Photoemission yield spectroscopy investigations of the electronic properties of copper phtalocyanine thin films UHV annealed and exposed to oxygen

Szuber

Szczepaniak

Kochowski

et al. 1994

Physica Status Solidi (b)

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Introduction Considerable efforts have been made during the last two decades in order to understand the electronic properties of phthalocyanine (Pc) compounds, well-known organic materials with interesting semiconducting [ 1 to 31 and catalytic [4] properties. Because of both high temperature and high chemical stability [5], they became widely used in thin film technology for specific optoelectronic devices [6], solar cells [7], and gas sensors [8].As for the most popular copper phthalocyanine (CuPc) thin films, up to now only UPS [9 to 131, SPS [14, 151, and EELS [16] methods have been used to study their electronic properties. In the earliest UPS studies of Vilesov et al. [9], reexamined by Schechtman and Spicer [lo], only the optical density of states in the upper part of the valence band up to -7 eV has been determined. It was characteristic of the conjugated inner ring of the main molecule and found to be in rather weak agreement with the free-electron molecular orbital calculations [ll]. Thereafter, Pong and Smith [12], and Hoechst et al. [13] have studied the copper phthalocyanine (CuPc) photoemission spectra for the photon energy range of 7 to 23 eV, but only for the higher photon energies they observed the structure characteristic of the optical density of states. In addition, the electron mean free path for energies larger than 1.5 eV above the valence band was estimated to be about 1 nm [12]. The electronic states near the top of the valence band have also been observed in the surface photovoltage spectroscopy (SPS) experiments of Dahlberg and Musser [14, 151 as well as in electron loss spectroscopy (EELS) studies of Tada et al. [16].Because of the limited energy range and sensitivities of the above-mentioned conventional methods, many questions concerning the electronic properties of the copper phthalocyanine (CuPc) thin films still remain unanswered. Investigations using other techniques are expected to give new and complementary information.One of the best and suitable methods for this purpose seems to be photoemission yield spectroscopy (PYS), developed by the group of Sebenne in Paris [17]. It consists in measuring the total number of photoemitted electrons per incident photon at a given light energy E (usually up to 6.2 eV). Because of the large dynamic range (up to eight orders of magnitude) and high energy resolution (up to 0.02 eV), PYS allows the determination, among others, of the work function cp and the ionization energy @. Moreover, with the debatable, but

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Electronic properties of the iron phthalocyanine thin films UHV annealed and exposed to oxygen

Cited by 9 publications

References 13 publications

Chemistry and electronic properties of ferromagnetic metal‐organic semiconductor interfaces: Fe on CuPc

Chemistry and electronic properties of ferromagnetic metal‐organic semiconductor interfaces: Fe on CuPc

Scanning Tunneling Microscopy of Metal Phthalocyanines: d⁶ and d⁸ Cases

Photoemission yield spectroscopy investigations of the electronic properties of copper phtalocyanine thin films UHV annealed and exposed to oxygen

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Electronic properties of the iron phthalocyanine thin films UHV annealed and exposed to oxygen

Cited by 9 publications

References 13 publications

Chemistry and electronic properties of ferromagnetic metal‐organic semiconductor interfaces: Fe on CuPc

Chemistry and electronic properties of ferromagnetic metal‐organic semiconductor interfaces: Fe on CuPc

Scanning Tunneling Microscopy of Metal Phthalocyanines: d6 and d8 Cases

Photoemission yield spectroscopy investigations of the electronic properties of copper phtalocyanine thin films UHV annealed and exposed to oxygen

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Scanning Tunneling Microscopy of Metal Phthalocyanines: d⁶ and d⁸ Cases