Silicon-CMOS Compatible In-Situ CCVD Grown Graphene Transistors with Ultra-High On/Off-Current Ratio

By means of catalytic chemical vapor deposition (CCVD) in-situ grown monolayer graphene field-effect transistors (MoLGFETs) and bilayer graphene transistors (BiLGFETs) are realized directly on oxidized silicon substrate without the need to transfer graphene layers. In-situ grown MoLGFETs exhibit the expected Dirac point together with the typical low on/off-current ratios. In contrast, BiLGFETs possess unipolar p-type device characteristics with an extremely high on/off-current ratio up to 1E7. The complete fabrication process is silicon CMOS compatible. This will allow a simple and low-cost integration of graphene devices for nanoelectronic applications in a hybrid silicon CMOS environment.Comment: 16 pages, 4 figure

Identification of DNA methylation biomarkers from Infinium arrays

Epigenetic modifications of DNA, such as cytosine methylation are differentially abundant in diseases such as cancer. A goal for clinical research is finding sites that are differentially methylated between groups of samples to act as potential biomarkers for disease outcome. However, clinical samples are often limited in availability, represent a heterogeneous collection of cells or are of uncertain clinical class. Array based methods for identification of methylation provide a cost effective method to survey a proportion of the methylome at single base resolution. The Illumina Infinium array has become a popular and reliable high throughput method in this field and are proving useful in the identification of biomarkers for disease. Here, we compare a commonly used statistical test with a new intuitive and flexible computational approach to quickly detect differentially methylated sites. The method rapidly identifies and ranks candidate lists with greatest inter-group variability whilst controlling for intra-group variability. Intuitive and biologically relevant filters can be imposed to quickly identify sites and genes of interest

Transfer-free fabrication of graphene transistors

We invented a method to fabricate graphene transistors on oxidized silicon wafers without the need to transfer graphene layers. To stimulate the growth of graphene layers on oxidized silicon a catalyst system of nanometer thin aluminum/nickel double layer is used. This catalyst system is structured via liftoff before the wafer enters the catalytic chemical vapor deposition (CCVD) chamber. In the subsequent methane based growth process monolayer graphene field-effect transistors (MoLGFETs) and bilayer graphene transistors (BiLGFETs) are realized directly on oxidized silicon substrate, whereby the number of stacked graphene layers is determined by the selected CCVD process parameters, e.g. temperature and gas mixture. Subsequently, Raman spectroscopy is performed within the channel region in between the catalytic areas and the Raman spectra of fivelayer, bilayer and monolayer graphene confirm the existence of graphene grown by this silicon-compatible, transfer-free and in-situ fabrication approach. These graphene FETs will allow a simple and low-cost integration of graphene devices for nanoelectronic applications in a hybrid silicon CMOS environment.Comment: 15 pages, 4 figure

Transfer-free Grown Bilayer Graphene Transistors for Digital Applications

We invented a novel method to fabricate graphene transistors on oxidized silicon wafers without the need to transfer graphene layers. By means of catalytic chemical vapor deposition (CCVD) the in-situ grown bilayer graphene transistors (BiLGFETs) are realized directly on oxidized silicon substrate, whereby the number of stacked graphene layers is determined by the selected CCVD process parameters, e.g. temperature and gas mixture. BiLGFETs exhibit ultra-high on/off-current ratios of 107 at room temperature, exceeding previously reported values by several orders of magnitude. This will allow a simple and low-cost integration of graphene devices for digital nanoelectronic applications in a hybrid silicon CMOS environment for the first time.Comment: 7 pages, 4 figures. arXiv admin note: substantial text overlap with arXiv:1112.4320, arXiv:1111.639

Novel Electrostatically Doped Planar Field-Effect Transistor for High Temperature Applications

In this paper, we present experimental results and simulation data of an electrostatically doped and therefore voltage-programmable, planar, CMOS-compatible field-effect transistor (FET) structure. This planar device is based on our previously published Si-nanowire (SiNW) technology. Schottky barrier source/drain (S/D) contacts and a silicon-on-insulator (SOI) technology platform are the key features of this dual-gated but single channel universal FET. The combination of two electrically independent gates, one back-gate for S/D Schottky barrier modulation as well as channel formation to establish Schottky barrier FET (SBFET) operation and one front-gate forming a junctionless FET (JLFET) for actual current control, significantly increases the temperature robustness of the device.Comment: 18 pages, 11 figure

A comparative approach to understanding tissue-specific expression of uncoupling protein 1 expression in adipose tissue

Peer reviewedPublisher PD

Optimal regulatory strategies for metabolic pathways in Escherichia coli depending on protein costs

While previous studies have shed light on the link between the structure of metabolism and its transcriptional regulation, the extent to which transcriptional regulation controls metabolism has not yet been fully explored. In this work, we address this problem by integrating a large number of experimental data sets with a model of the metabolism of Escherichia coli. Using a combination of computational tools including the concept of elementary flux patterns, methods from network inference and dynamic optimization, we find that transcriptional regulation of pathways reflects the protein investment into these pathways. While pathways that are associated to a high protein cost are controlled by fine‐tuned transcriptional programs, pathways that only require a small protein cost are transcriptionally controlled in a few key reactions. As a reason for the occurrence of these different regulatory strategies, we identify an evolutionary trade‐off between the conflicting requirements to reduce protein investment and the requirement to be able to respond rapidly to changes in environmental conditions

Drawn Stories, Moving Images. Comic Books and their Screen Adaptations

The comic transcends the merely entertaining, and fans of comics become engaged and invested in the field through a range of activities. Major cities host regular comic conventions, attracting hundreds of thousands of attendees each year, who search for special issues of their favourite comic-book series, meet artists, attend workshops and buy merchandise. Many fans do not stop at just attending conventions; they do so dressed as their favourite comic characters or wearing badges, buttons, T-shirts or sweaters with images of those characters on them. In other words: many fans do ot merely consume comic books; rather, they arrange a considerable part of their lives around them and in some cases even embody their heroes, that is, they copy their behaviour and their language. The comic universe, the comic books and the range of activities emerging out of them and around them become a meaningful universe for fans