Tungsten polyoxometalate molecules as active nodes for dynamic carrier exchange in hybrid molecular/semiconductor capacitors

Journal Article · Tue Oct 14 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4897397· OSTI ID:22305790

Douvas, A. M.; Normand, P.; Argitis, P.; Glezos, N. ^[1]; Tsikritzis, D.; Kennou, S. ^[2]

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1. Institute of Nanoscience and Nanotechnology, NCSR Demokritos, Aghia Paraskevi, Athens 15310 (Greece)
2. Department of Chemical Engineering, University of Patras, University Campus, Patras 26504 (Greece)

In this work we study the utilization of molecular transition metal oxides known as polyoxometalates (POMs), in particular the Keggin structure anions of the formula PW₁₂O₄₀³⁻, as active nodes for potential switching and/or fast writing memory applications. The active molecules are being integrated in hybrid Metal-Insulator/POM molecules-Semiconductor capacitors, which serve as prototypes allowing investigation of critical performance characteristics towards the design of more sophisticated devices. The charging ability as well as the electronic structure of the molecular layer is probed by means of electrical characterization, namely, capacitance-voltage and current-voltage measurements, as well as transient capacitance measurements, C (t), under step voltage polarization. It is argued that the transient current peaks observed are manifestations of dynamic carrier exchange between the gate electrode and specific molecular levels, while the transient C (t) curves under conditions of molecular charging can supply information for the rate of change of the charge that is being trapped and de-trapped within the molecular layer. Structural characterization via surface and cross sectional scanning electron microscopy as well as atomic force microscopy, spectroscopic ellipsometry, UV and Fourier-transform IR spectroscopies, UPS, and XPS contribute to the extraction of accurate electronic structure characteristics and open the path for the design of new devices with on-demand tuning of their interfacial properties via the controlled preparation of the POM layer.

• OSTI ID: 22305790
• Journal Information: Journal of Applied Physics, Vol. 116, Issue 14; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATOMIC FORCE MICROSCOPY
CAPACITORS
CARRIERS
ELECTRONIC STRUCTURE
ELLIPSOMETRY
FOURIER TRANSFORM SPECTROMETERS
INFRARED SPECTRA
LAYERS
MEMORY DEVICES
POLARIZATION
SCANNING ELECTRON MICROSCOPY
SEMICONDUCTOR MATERIALS
SURFACES
TRANSIENTS
TRAPPING
TUNGSTEN
ULTRAVIOLET SPECTRA
X-RAY PHOTOELECTRON SPECTROSCOPY