Electronic Devices And Circuits By Jb Gupta Pdf Download _VERIFIED_
Electronic Devices And Circuits By Jb Gupta Pdf Download
In the search for a better electronic material for future OTFTs, 112 transition metal dichalcogenides (TMDs) have emerged as a new class of material for bottom-gate-transistor fabrication. 113 TMDs show a high carrier mobility due to their direct bandgap, which makes them attractive for applications such as electronic devices, optoelectronic devices, and biosensors. However, (i) TMDs have a low solubility in non-polar solvents, which makes it difficult to modify or functionalize the surface of TMDs, (ii) high processing temperatures are required to form TMDs electronic devices and circuits because of their intrinsic properties, (iii) and the etching process is required to remove the native TMDs during device fabrication as the materials do not adhere to the underlying SiO2 surface, therefore rendering the OTFTs fabrication processes expensive and more difficult. 113 I’mito et al. 107 reported 107 a single-gate polymer OTFTs using poly(9,9-di-n-hexyl-2,7-fluorene) (PFN) and poly(2,5-(9,9-dihexylfluorene)-alt-5,7-(2,7-diethyloctyloxy)-2,3,6,7-perylene). PFN is insoluble in common solvents such as toluene, benzene, and chloroform, and consequently, (i) it is impossible to directly etch TMDs using standard TFT processing and etching techniques, (ii) the PFN polymer readily forms crystalline structures when dissolved in organic solvents, which makes it impossible to spin-cast the solution, (iii) the solution requires a very fast and complete sonication treatment to remove the micrometer-sized domains of crystalline structures, and (iv) the solution is highly toxic and aggressive, making it impossible to integrate spin-coating into a roll-to-roll manufacturing process for large scale manufacturing.
The main working principle of the electronic skin is that an applied electronic stimulus is converted into a mechanical stimulus which is then sensed by the touch sensor that is integrated on the skin. The skin ‘recognizes’ the applied stimulus based on the associated tactile properties and outputs the sensory data to the processing electronics, which in turn processes the data and generates the appropriate output. Thus the electronic skin has an internal processing section which is interfaced with the external stimulus. Electrical response characteristics can vary with the intrinsic properties of the electronic skin such as skin impedance, contact and non-contact impedance as well as the mechanical characteristics of the skin. Thus, there is a need to calibrate and retune the electronic skin to eliminate the inter- and intra-device variations. The primary stimuli used are vibration, heat and pressure. The vibration-based electronic skin devices are based on various principles including piezoelectric and triboelectric actuation mechanisms. The piezoelectric devices use the piezoelectric effect which is the change in electrical charge when a material is deformed. The triboelectric devices rely on the triboelectric effect, which is the induction of an electric charge on a material by a partial frictional electrification of the surface from mechanical contact. Another operating principle of the electronic skin is the use of photoinduced current flow. Such electronic skin devices require external light source to induce current. One of the important features of the electronic skin is that it offers a ‘visually clean’ interface between the external and internal world. The user or environment does not sense any spatial or electronic artefacts. Furthermore, it is also possible to integrate multiple sensory data using wireless or wired interface circuits, which is of primary importance for applications where the data is to be transmitted to and processed in distant locations. The existing literature has confirmed the possibility of employing electronic skin as a primary interface between user and machine.