TY - GEN A1 - Tallarida, Massimo A1 - Das, Chittaranjan A1 - Cibrev, Dejan A1 - Kukli, Kaupo A1 - Tamm, Aile A1 - Ritala, Mikko A1 - Lana-Villarreal, Teresa A1 - Gómez, Roberto A1 - Leskelä, Markku A1 - Schmeißer, Dieter T1 - Modification of Hematite Electronic Properties with Trimethyl Aluminum to Enhance the Efficiency of Photoelectrodes T2 - The Journal of Physical Chemistry Letters N2 - The electronic properties of hematite were investigated by means of synchrotron radiation photoemission (SR-PES) and X-ray absorption spectroscopy (XAS). Hematite samples were exposed to trimethyl aluminum (TMA) pulses, a widely used Al-precursor for the atomic layer deposition (ALD) of Al2O3. SR-PES and XAS showed that the electronic properties of hematite were modified by the interaction with TMA. In particular, the hybridization of O 2p states with Fe 3d and Fe 4s4p changed upon TMA pulses due to electron inclusion as polarons. The change of hybridization correlates with an enhancement of the photocurrent density due to water oxidation for the hematite electrodes. Such an enhancement has been associated with an improvement in charge carrier transport. Our findings open new perspectives for the understanding and utilization of electrode modifications by very thin ALD films and show that the interactions between metal precursors and substrates seem to be important factors in defining their electronic and photoelectrocatalytic properties. KW - Hematite KW - Atomic Layer deposition KW - Photoelectrode KW - electro-catalysis KW - TMA KW - efficiency enhancement Y1 - 2014 U6 - https://doi.org/10.1021/jz501751w VL - 5 IS - 20 SP - 3582 EP - 3587 ER - TY - GEN A1 - Kukli, Kaupo A1 - Dimri, Mukesh Chandra A1 - Tamm, Aile A1 - Kemell, Marianna A1 - Käämbre, Tanel A1 - Vehkamäki, Marko A1 - Puttaswamy, Manjunath A1 - Stern, Raivo A1 - Kuusik, Ivar A1 - Kikas, Arvo A1 - Tallarida, Massimo A1 - Schmeißer, Dieter A1 - Ritala, Mikko A1 - Leskelä, Markku T1 - Structural and Magnetic Studies on Iron Oxide and Iron-Magnesium Oxide Thin Films Deposited Using Ferrocene and (Dimethylaminomethyl)ferrocene Precursors T2 - ECS Journal of Solid State Science and Technology N2 - Iron oxide and magnesium-doped iron oxide films were grown by atomic layer deposition in the temperature range of 350–500 ◦C from ferrocene, (dimethylaminomethyl)ferrocene, magnesiumβ-diketonate, and ozone. Phase composition of the films depended on the deposition temperature, as magnetite and/or maghemite tended to form instead of hematite upon lowering the temperature. Iron oxide layers were also mixed with magnesium oxide by alternate deposition of MgO and Fe2O3 which also favored the formation of magnetite or maghemite structure prior to hematite. Scanning electron microscopy implied the smoothening of the films after doping with magnesium oxide. Magnetometry was used to study the effects of temperature and doping levels on the magnetic properties of the films. KW - iron oxide KW - iron magnesium oxide KW - GIXRD KW - Raman spectroscopy KW - X-Ray absorption spectroscopy (XAS) KW - scanning electron microscopy (SEM) KW - magnetization Y1 - 2013 U6 - https://doi.org/10.1149/2.004303jss SN - 2162-8769 VL - 2 IS - 3 SP - N45 EP - N54 ER - TY - GEN A1 - Tamm, Aile A1 - Kemell, Marianna A1 - Kozlova, Jekaterina A1 - Sajavaara, Timo A1 - Tallarida, Massimo A1 - Kukli, Kaupo A1 - Sammelselg, V. A1 - Ritala, Mikko A1 - Leskelä, Markku T1 - Atomic Layer Deposition and Characterization of Erbium Oxide-Doped Zirconium Oxid Thin Films T2 - Journal of The Electrochemical Society KW - atomic Layer deposition KW - Erbium KW - Zirconium KW - Oxid-Doped Y1 - 2010 VL - 157 IS - 10 SP - G193 EP - G201 ER -