Validity of the parabolic effective mass approximation in silicon and germanium n-MOSFETs with different crystal orientations

This paper investigates the validity of the parabolic effective mass approximation (EMA), which is almost universally used to describe the size and bias-induced quantization in n-MOSFETs. In particular, we compare the EMA results with a full-band quantization approach based on the linear combination of bulk bands (LCBB) and study the most relevant quantities for the modeling of the mobility and of the on-current of the devices, namely, the minima of the 2-D subbands, the transport masses, and the electron density of states. Our study deals with both silicon and germanium n-MOSFETs with different crystal orientations and shows that, in most cases, the validity of the EMA is quite satisfactory. The LCBB approach is then used to calculate the values of the effective masses that help improve the EMA accuracy. There are crystal orientations, however, where the 2-D energy dispersion obtained by the LCBB method exhibits features that are difficult to reproduce with the EMA model

Strijd om het klimaat: de beeldvorming over klimaatverandering tijdens de klimaattop te Cancún in Vlaamse kwaliteitskranten

This paper reports on the results of a qualitative content analysis of climate change coverage by two Flemish quality newspapers in the context of the Cancun climate summit. Important similarities as well as differences were found between both newspapers in terms of underlying assumptions regarding international relations

Design trade-offs in amorphous indium gallium zinc oxide thin film transistor based bio-signal sensing front-ends

With the advent of the Internet of things, wearable sensing devices are gaining importance in our daily lives for applications like vital signal monitoring during sport and health diagnostics. Amorphous indium gallium zinc oxide (a-IGZO) thin film transistors (TFTs) fabricated on flexible large-area substrates are a very interesting platform to build wearable sensing devices due to their flexibility, conformability to the human body, and low cost. For this paper four different bio-signal sensing front-end circuits based on a-IGZO TFTs are designed, fabricated, measured and compared, focusing on three performance indicators which are in a trade-off: power efficiency factor (PEF), area occupation and input impedance. Considering a 200 Hz bandwidth, the measured PEF varies between 4.7 × 105 and 7.5 × 106. The area occupation spans from 4.2 to 37 mm2, while the input impedance at 1 Hz varies from 5.3 to 55.3 MΩ. The front-ends based on diode-load amplifiers are compact but have the lowest input impedance and need external capacitors; a front-end exploiting positive feedback impedance boosting has the highest input impedance and is fully integrated on foil, but occupies the largest area

A conformable active matrix LED display

Conformable and stretchable displays can be integrated on complex surfaces. Such a display can assume the shape of a conformed surface by simultaneous multi-dimensional stretching and bending. Such technology provides new opportunities in the field of display applications, for example wearable displays integrated or embedded in a textile or onto complex surfaces in automotive interiors. In this work we present a conformable active matrix display using LEDs mounted on an amorphous Indium-Gallium-Zinc Oxide (a-IGZO) TFT backplane. A two-transistor and one capacitor (2T-1C) pixel engine based backplane, fabricated on polyimide substrate, is used to drive LEDs. Rigid LED pixels are connected via meandered copper film. The meander interconnections have been optimized with respect to their electrical and mechanical properties to provide a display with a 2 mm pitch between the pixels and good conformability. At an operating supply voltage of 7 V, the average brightness of the display exceeds 170 cd/m2