@misc{TallaridaDasCibrevetal., author = {Tallarida, Massimo and Das, Chittaranjan and Cibrev, Dejan and Kukli, Kaupo and Tamm, Aile and Ritala, Mikko and Lana-Villarreal, Teresa and Gómez, Roberto and Leskel{\"a}, Markku and Schmeißer, Dieter}, title = {Modification of Hematite Electronic Properties with Trimethyl Aluminum to Enhance the Efficiency of Photoelectrodes}, series = {The Journal of Physical Chemistry Letters}, volume = {5}, journal = {The Journal of Physical Chemistry Letters}, number = {20}, doi = {10.1021/jz501751w}, pages = {3582 -- 3587}, abstract = {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.}, language = {en} } @misc{KukliDimriTammetal., author = {Kukli, Kaupo and Dimri, Mukesh Chandra and Tamm, Aile and Kemell, Marianna and K{\"a}{\"a}mbre, Tanel and Vehkam{\"a}ki, Marko and Puttaswamy, Manjunath and Stern, Raivo and Kuusik, Ivar and Kikas, Arvo and Tallarida, Massimo and Schmeißer, Dieter and Ritala, Mikko and Leskel{\"a}, Markku}, title = {Structural and Magnetic Studies on Iron Oxide and Iron-Magnesium Oxide Thin Films Deposited Using Ferrocene and (Dimethylaminomethyl)ferrocene Precursors}, series = {ECS Journal of Solid State Science and Technology}, volume = {2}, journal = {ECS Journal of Solid State Science and Technology}, number = {3}, issn = {2162-8769}, doi = {10.1149/2.004303jss}, pages = {N45 -- N54}, abstract = {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.}, language = {en} } @misc{TammKemellKozlovaetal., author = {Tamm, Aile and Kemell, Marianna and Kozlova, Jekaterina and Sajavaara, Timo and Tallarida, Massimo and Kukli, Kaupo and Sammelselg, V. and Ritala, Mikko and Leskel{\"a}, Markku}, title = {Atomic Layer Deposition and Characterization of Erbium Oxide-Doped Zirconium Oxid Thin Films}, series = {Journal of The Electrochemical Society}, volume = {157}, journal = {Journal of The Electrochemical Society}, number = {10}, pages = {G193 -- G201}, language = {en} }