Nowadays, the haptic effect is used and developed for many applications—particularly in the automotive industry, where the mechanical feedback induced by a haptic system enables the user to receive information while their attention is kept on the road and on driving. This article presents the development of a vibrotactile button based on printed piezoelectric polymer actuation. Firstly, the characterization of the electro-active polymer used as the actuator and the development of a model able to predict the electromechanical behavior of this device are summarized. Then, the design of circular membranes and their dynamic characterization are presented. Finally, this work is concluded with the construction of a fully functional demonstrator, integrating haptic buttons leading to a clear haptic sensation for the user.

We have investigated the influence of the semiconductor thickness varying by almost two orders of magnitude on the transfer and output characteristics of top gate staggered organic field-effect transistors. We observe that the mobility in the saturation regime is almost constant in the thickness range studied. In contrast, the subthreshold slope and the threshold voltage are highly impacted by the semiconductor thickness, and in particular they showed a common optimum thickness value. On both sides of this optimum we observe a loss in performances, which are tentatively attributed to different mechanisms.

This paper presents a printed organic complementary technology on flexible plastic substrate with high performance N and P-type Organic Thin Film Transistors (OTFTs), based on small-molecule organic semiconductors in solution. Challenges related to the integration of both OTFT types in a common complementary flow are addressed, showing the importance of surface treatments. Data on single devices and elementary complementary digital circuits (inverters and ring oscillators) are presented, demonstrating that a robust and reliable flow with high electrical performances can be established for printed organic devices.

In this article, threshold-voltage V _TH instabilities under positive gate voltage stress V _GStress in GaN-on-Si devices are thoroughly investigated. Measurement-stress-measurement pBTI technique using ultrafast V _G ramp was applied in this study. PBTI transients performed at different V _GStress and several temperatures highlight the influence of two trap populations, one being related to Al ₂ O ₃ gate oxide defects and the other one to C _N acceptors in GaN lattice. Both trap populations are located close to the Al ₂ O ₃ /GaN interface and lead to V _TH instabilities via two different underlying mechanisms simulated by TCAD. PBTI transients obtained under several dc and ac stress conditions have also been modeled using capture emission time (CET) maps and allowed the identification of the two trap populations. Analysis of the temperature-dependent CET maps gives an activation energy of 0.8-0.9 eV related to C _N traps and an energy range between 0.7 and 1.5 eV ascribed to Al ₂ O ₃ defects above the GaN conduction band energy. This study provides a better understanding of the underlying physical mechanisms, leading to BTI degradation in GaN-HEMT technologies.

In this paper, threshold voltage V TH instabilities under positive gate voltage stress (V GStress ) are thoroughly investigated on GaN-on-Si Enhancement-mode MOS-channel HEMTs. An analysis of pBTI transients performed at several V GStress and temperatures (T) reveals two trap populations close to the Al 2 O 3 /GaN interface namely (1) C N acceptors in the GaN substrate, and (2) defects in the Al 2 O 3 gate oxide. Both trap populations lead to V TH instabilities via different underlying mechanisms as evidenced by TCAD simulations. At V GStress < 1.5 V, V TH drifts are ascribed to C N traps ionization localized at 0.8-0.9eV above the valence band (E v ). At higher VGstress, electron trapping also occurs in Al 2 O 3 defects leading to stronger V TH degradation. DC & AC pBTI transients have been modeled using Capture Emission Time (CET) map approach, which allowed the identification of both trap populations. Temperature-dependent CET maps extraction reveals a strong activation of C N traps with temperature, and confirms Arrhenius analysis consistency. This study provides a deep understanding of BTI reliability in GaN-HEMT technologies.

This article presents a manufacturing process and the electro-mechanical characterization of actuators made with electroactive polymers based on a PDVF terpolymer. Indeed, the PVDF-TrFE-CFE presents a high electrostrictive strain under electrical field. By introducing it in a metal-insulator-metal structure processed on a thin PEN foil, cantilevers were realized on flexible substrates. The cantilevers fabrication process is described, and their characterization is done by the measurement of the displacement bending and the consequent calculation of the induced strain under electric field. A theoretical model is proposed and validated by the experimental measurements.