Compatibilisation of various PLA/thermoplastic elastomer blends with diisocyanate coupling agent

Poly(lactic acid) (PLA) is characterised by its inherent brittleness, a detrimental feature for the production of durable bioplastics. PLA has been toughened by a low amount (12?wt-%) of various thermoplastic elastomers (TPE) including poly(ether-b-ester) (PEEs), poly(ether-b-amide) (PEBA) and poly(ether-b-urethane) (PEU). PLA–TPE blends were prepared by using a twin screw extruder. Ductility and impact resistance can be slightly improved with the incorporation of TPEs but but PEBA appears the most efficient. Reactive compatibilisation has been performed with the addition in the melt of a low amount (2?wt-%) of 4,4-methylene diphenyl diisocyanate. All compatibilised blends exhibit high toughness with similar ductility. These blends preserve good stiffness and high tensile strength. Compatibilised PEBA blends can be considered as super tough poly(lactic acid) materials. This work confirms that the flexibility of the elastomer together with the quality of the interfacial adhesion between the rigid (PLA) and the soft (TPE) phases are the primary factors influencing the toughness.     

The metal/organic monolayer interface in molecular electronic devices

The metal/molecules/metal is the basic device used to measure the electronic properties of organic molecules envisioned as the key components in molecular-scale devices (molecular diode, molecular wire, molecular memory, etc.). This review paper describes the main techniques used to fabricate a metal/molecules/metal device (or more generally electrode/molecules/electrode junctions, with electrodes made of metal or semiconductor). We discuss several problems encountered for the metallization of organic monolayers. The organic/electrode interface plays a strong role in the electronic properties of these molecular devices. We review some results on the relationships between the nature of the electrode/molecule interface (physisorbed or chemisorbed, evaporated metal electrode, mechanical contact, etc.) and the electronic transport properties of these molecular-scale devices. We also discuss the effects of symmetric versus asymmetric coupling of the two ends of the molecules with the electrodes.     

Evidence of acceptor-like oxide defects created by hot-carrierinjection in n-MOSFET's: a charge-pumping study

Charge-pumping measurements and simulation of charge-pumping characteristics demonstrate that acceptor-like oxide traps (i.e. negatively charged when occupied by an electron and neutral when occupied by a hole) are created in the gate-drain overlap region of an n-MOSFET subjected to hot-electron and/or hot-hole injections (HEI and/or HHI). These traps are located in the gate-drain overlap region, and it is emphasized that the charge-pumping technique is able to detect them in addition to the damages in the channel     

Comment on “hot-hole-induced negative oxide charges inn-MOSFETs” [and reply]

For the original article see ibid., vol. 42, p. 1473 (1995). The commenters state that a clear proof of the generation of electron traps under hot-hole injections and a clear distinction from the effect of stress-induced interface states have been given by them in a paper (see ibid., vol. 40, p. 773, 1993) previous to the work reported by Weber et al. Also, the consequences of the creation of these defects in AC lifetime predictions have been extensively discussed by Mistry and Doyle (see ibid., vol. 40, p.96, 1993 and IEEE Electron Device Lett., vol. 12, p. 492, 1991). Detrapping experiments extensively used by Weber et al. are another independent evidence of such a creation of electron traps by hot-hole injections in n-MOSFET's, and the suggestion of new data acquisition to take into account the effects of such electron traps in the determination of lifetimes is a key point to further development, especially as far as operating conditions of analog CMOS circuits are considered. In reply the authors remark that the paper by Vuillaume et al. was inadvertently left off the reference list as they were unaware of its existence and as the paper is certainly relevant to the issue being discussed, it should have been included in the reference list. Also the authors give several arguments why they believe that their technique using time-dependent changes in the multiplication factor M is superior to either charge pumping or floating gate measurements for differentiating between the two types of negative charge created by hot-hole injection: interface traps and oxide traps     

Integrating Multiple Resistive Memory Devices on a Single Carbon Nanotube

Nano‐objects would be of great interest for the development of new types of electronic circuits if one could combine their nanometer scale with original functionalities beyond the conventional transistor action. However, the associated circuit architectures will have to handle the increasing variability and defect rate intrinsic to the nanoscale. In this context, there is a very fast growing interest for memory devices, and in particular resistive memory devices, used as building blocks in reconfigurable circuits tolerant to defects and variability. It was recently shown that optically gated carbon nanotube field effect transistors (OG‐CNTFETs) based on large assemblies of nanotubes covered by an organic photoconductive thin film can be operated as programmable resistors and thus used as artificial synapses in circuits with function‐learning capabilities. Here, the potential of such approach is evaluated in terms of scalability by integrating and addressing several individually programmable resistances on a single carbon nanotube. In addition, the charge storage mechanism can be controlled at a length scale smaller than the device length allowing to also program the direction in which the current flows. It thus demonstrates that a single nanotube section can combine all‐in‐one the properties of an analog resistive memory and of a rectifying diode with tunable polarity.     

Hot-carrier injections in SiO2

We review the hot-carrier injection phenomena in gate-oxide and the related degradation in silicon MOSFETs. We discuss the basic degradation mechanisms and the nature of the created defects by carrier injections through the gate-oxide. Emphasis is put on the discussion of dynamic hot-carrier injections in MOSFETs and on the stress induced leakage currents in very thin (< 5 nm) gate-oxide.     

Metabolism of fluorinated mescallins by Pieris brassicae (Insect, Lepidoptera) (author's transl)

The action of alpha-fluorinated mescalins on induction of diapause in the cabbage butterfly, Pieris brassicae, has been studied. The introduction of fluorine into mescalin has no influence on this activity. This result suggests solvolysis of fluorine and in vivo formation of a common ethylimine intermediate. Activity decreases, however, with substitution of the nitrogen.     

Characterization of oxide trap and interface trap creation duringhot-carrier stressing of n-MOS transistors using the floating-gatetechnique

A technique has been developed to differentiate between interface states and oxide trapped charges in conventional n-channel MOS transistors. The gate current is measured before and after stress damage using the floating-gate technique. It is shown that the change in the I_g-V_g characteristics following the creation and filling of oxide traps by low gate voltage stress shows distinct differences when compared to that which occurs for interface trap creation at mid gate voltage stress conditions, permitting the identification of hot-carrier damage through the I_g- V_g characteristics. The difference is explained in terms of the changes in occupancy of the created interface traps as a function of gate voltage during the I_g-V _g measurements