Andreas Fischer

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We demonstrate humidity sensing using a change of the electrical resistance of single-layer chemical vapor deposited (CVD) graphene that is placed on top of a SiO2 layer on a Si wafer. To investigate the selectivity of the sensor towards the most common constituents in air, its signal response was characterized individually for water vapor (H2O), nitrogen(More)
Three-dimensional (3D) integration of electronics and/or MEMS-based transducers is an emerging technology that vertically interconnects stacked dies using through silicon vias (TSVs). They enable the realization of devices with shorter signal lengths, smaller packages and lower parasitic capac-itances, which can result in higher performance and lower costs(More)
Graphene membranes act as highly sensitive transducers in nanoelectromechanical devices due to their ultimate thinness. Previously, the piezoresistive effect has been experimentally verified in graphene using uniaxial strain in graphene. Here, we report experimental and theoretical data on the uni- and biaxial piezoresistive properties of suspended graphene(More)
Through silicon vias (TSVs) are used e.g. to create electrical connections through MEMS wafers or through silicon interposers used in 2.5D packaging. Currently available technologies do not address situations in which TSVs through unthinned wafers have to withstand large temperature variations. We propose using ferromagnetic Invar metal alloy for this(More)
This paper demonstrates flexible and stretchable microneedle patches that combine soft and flexible base substrates with hard and sharp stainless steel microneedles. An elastomeric polymer base enables conformal contact between the microneedle patch and the complex topography and texture of the underlying skin, while robust and sharp stainless steel(More)
Background: Non pigmented eccrine poroma is a benign tumor that can have dermoscopic features mimicking malign neoplasias. The characteristic vascular pattern of this tumor hasn't been established. We found a scarcely reported vas-cular pattern, which can be useful to distinguish this tumor from malignant ones and propose a new nomenclature to these vessels(More)
Multiple access interference (MAI) limits the system capacity of wireless communications systems applying code division multiple access (CDMA). Provided that channel knowledge is available in the transmitter, the transmitted signal can be pre-processed by multiuser transmission (MUT) methods. As optimization criterion, the bit error probability / rate (BER)(More)
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