Chemically specific identification of carbon in XPS imaging using Multivariate Auger Feature Imaging (MAFI)

Until now, a difficult prospect in XPS imaging has been the identification of similar chemical states of carbon. With the advent of novel nano-carbons such as nanotubes and graphene, the ability to easily and unambiguously identify materials of varying sp2/sp3 nature in XPS spectra and images is becoming increasingly important. We present herein methods for the identification of such species in XPS images by shifting focus from the traditionally analysed C1s region to the X-ray induced carbon Auger feature. By extracting the D-Parameter from XPS data, we have generated what we refer to as "D-Parameter Images", that clearly identify regions of different carbon hybridisation in an image of a graphite flake mounted on carbon tape, and areas of reduced graphene oxide (GO) in a laser-scribed GO film. This method is then enhanced by multivariate analysis, a technique we call "Multivariate Auger Feature Imaging", where the distinction between varying sp2 carbon content on a surface is improved

Voltage Controlled Hot Carrier Injection Enables Ohmic Contacts Using Au Island Metal Films on Ge

We introduce a new approach to creating low-resistance metalsemiconductor ohmic contacts, illustrated using high conductivity Au island metal films (IMFs) on Ge, with hot carrier injection initiated at low applied voltage. The same metallization process simultaneously allows ohmic contact to n-Ge and p-Ge, because hot carriers circumvent the Schottky barrier formed at metal/n-Ge interfaces. A 2.5x improvement in contact resistivity is reported over previous techniques to achieve ohmic contact to both n- and p- semiconductor. Ohmic contacts at 4.2 K confirm nonequilibrium current transport. Self-assembled Au IMFs are strongly orientated to Ge by annealing near the Au/Ge eutectic temperature. Au IMF nanostructures form, provided the Au layer is below a critical thickness. We anticipate that optimized IMF contacts may have applicability to many material systems. Optimizing this new paradigm for metalsemiconductor contacts offers the prospect of improved nanoelectronic systems and the study of voltage controlled hot holes and electrons.Peer reviewe

Crystallographic structure of ultrathin Fe films on Cu(100)

We report bcc-like crystal structures in 2-4 ML Fe films grown on fcc Cu(100) using scanning tunneling microscopy. The local bcc structure provides a straightforward explanation for their frequently reported outstanding magnetic properties, i.e., ferromagnetic ordering in all layers with a Curie temperature above 300 K. The non-pseudomorphic structure, which becomes pseudomorphic above 4 ML film thickness is unexpected in terms of conventional rules of thin film growth and stresses the importance of finite thickness effects in ferromagnetic ultrathin films.Comment: 4 pages, 3 figures, RevTeX/LaTeX2.0

Optimal conditions for gas cluster ion beams in studying inorganic interface species: improved chemical information at a ZnO interface

We have observed for the first time a subtle chemical change in the oxidation state of Zn at the interface between a ZnO thin film and a glass substrate using gas cluster ion beam (GCIB) depth-profiling. A combination of monoatomic and gas clusters was used for etching, allowing the removal of the surface rapidly using the monoatomic ion beam yet still yield a less damaged surface by removing the damaged layer using the argon GCIB as a final step. With this combined method, the depth-profile shows the transition of Zn from oxide to metal at the interface, which the monoatomic ion source if used alone would damage. This data indicates that the initial layers of the film did not undergo as much oxidation during the deposition compared with the rest of the film; therefore, metallic zinc resulted at the interface. We also examined the ZnO thin film under a range of conditions of argon ion profiling from monoatomic to cluster ions to study the most efficient method for depth-profiling of multiple layers of inorganic materials. The monoatomic ion beam does not show the transition phenomena at the interface, which was observed in cluster depth-profiling, probably because of atomic mixing effects. This suggests that care be taken in selection of etch parameters when studying interfaces. We recommend the combination of monoatomic sputtering followed by GCIB etching as the most efficient method for looking at interfaces of inorganic thin layers from the point of view of time taken and minimising damage at interface. Copyright © 2016 John Wiley & Sons, Ltd

Lainakatto Suomessa – taustat ja vaikutukset asuntoluotonmyöntöön

Työni päätavoitteena oli selvittää, kuinka luottolaitoslakiin kirjoitettu pykälä asuntolainojen enimmäisluototussuhteesta, eli niinkutsutusta lainakatosta tulee vaikuttamaan pankkien luotonmyöntöön Suomessa. Lisäksi työssäni selvitettiin, kuinka jo olemassaoleva Finanssivalvonnan suositus 10 prosentin omarahoitusosuudesta on muovannut pankkien luotonmyöntöä. Työn empiria tehtiin laadullisena tutkimuksena, jossa haastattelin kahden eri pankin asiantuntijaa lainakaton tiimoilta. Työn teoriaosuudessa käytiin läpi rahoituslaitosten toimintaa sekä luotonmyöntöä prosessina. Lisäksi työssä kerrottiin pankkitoiminnan sääntelystä ja valvonnasta sekä luottolaitosten riskienhallinnasta. Lisäksi työssä käytiin läpi hieman makrovakauspolitiikan keskeisiä elementtejä ja erityisesti lainakattoa makrovakauspolitiikan työkaluna. Työssäni käsiteltiin myös keinoja lainakattoon varautumiseksi, jossa keskeisenä elementtinä on ASP-järjestelmä. Ruotsissa lainakatto on ollut käytössä jo vuodesta 2010, joten halusin työssäni kertoa myös Ruotsin mallista ja verrata sitä suomalaiseen lainakattoon. Lainakaton keskeisenä tavoitteena on hillitä kotitalouksien ylivelkaantumista ja asuntojen hintojen nousun toisiaan vahvistavaa kierrettä. Tällä hetkellä näyttäisi siltä, että tässä markkinatilanteessa lainakatolle ei ole tilausta. Lainakatto voi kuitenkin tulevaisuudessa olla vielä oivallinen työkalu, mikäli asuntomarkkinat uhkaisivat ylikuumentua ja rahoitusmarkkinoiden vakaus vaarantuisi.The purpose of this study was to find out how loan ceiling will effect on mortgage granting in Finland. The objective was also to find out if the regulations about down payments given by the Financial Supervisor Authority have already affected mortgage granting. The study has been conducted by interviewing two specialists in financing. The information was gathered from literature, theinternet and by interviewing two specialists. In this thesis there is information about banking regulations, supervision and risk management in the Finnish banking business. Loan ceiling is also viewed from a wider point of view. The main purpose of loan ceiling is to maintain stability in household debts and housing market in Finland. Loan ceiling is a part of macrofinancial strategy and therefore there is also one chapter about marcofinancial policies in this thesis. Loan ceiling usually has the biggest impact on first time home buyers and therefore also ASP-system is presented. Loan ceiling has been part of Swedish mortgage granting strategy since 2010. Findings from the Swedish model are also explained and compared to Finnish model in this study. As told, the main purpose of loan ceiling is to maintain stability in household debts and housing market in Finland. At this moment it seems that there is no threat of a major boom in the housing market. Still there might be a time when loan ceiling can be very helpful tool in maintaining stability in the Finnish finance sector