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In this study, we investigate the influence of an overlap between the gate and source/drain regions of a-Si:H thin film transistors (TFTs) on their electrical characteristics under tensile or compressive strain through experiment and mechanical simulation. The strain distribution in the a-Si:H TFT for a bending radius of 2mm reveals that the strain at both ends of the TFT is ten times larger than that at the source-drain current path. The overlap lowers the stress sustained by the TFT in the region comprised between the channel and the gate insulator; therefore, TFTs with the overlap operate even at a tensile strain of 2.54%. In particular, the overlap is remarkably effective on relaxing the stress sustained in the interface between the gate insulator and the gate electrode, consequently improving the electrical stability of the bent TFT. [ABSTRACT FROM AUTHOR]

In this study, we report the electrical and mechanical characteristics of fully transparent indium zinc oxide (IZO) thin-film transistors (TFTs) fabricated on stress-relieving bendable substrates. An IZO TFT on a stress-relieving substrate can operate normally at a bending radius of 6mm, while an IZO TFT on a normal plastic substrate fails to operate normally at a bending radius of 15mm. A plastic island with high Young's modulus embedded on a soft elastomer layer with low Young's modulus plays the role of a stress-relieving substrate for the operation of the bent IZO TFT. The stress and strain distributions over the IZO TFT will be analyzed in detail in this paper. [ABSTRACT FROM AUTHOR]

HgTe nanocrystal-based thin-film transistors (TFTs) with AI2O3 top-gate dielectrics were fabricated on glass substrates using sintered HgTe nanocrystals as the channel layers. To the best of our knowledge, this is the first report on the fabrication of nanocrystal-based TFTs on glass substrates. Colloidal HgTe nanocrystal films were first formed on the glass substrates by spin-coating. The HgTe nanocrystal films were then sintered at 150 °C, leading to a dramatic increase in their conductance, compared with the as-deposited films. The TFTs fabricated in this letter exhibit the typical characteristics of p-channel transistors with a field-effect mobility of 1.04 cm²/V · s, a threshold voltage of +0.2 V, and an ON/OFF current ratio of 1 × 10³. These results suggest that spin-coating and sintering at a low temperature enable the simple and low-cost fabrication of nanocrystal-based TFTs on glass substrates. [ABSTRACT FROM AUTHOR]

In this study, we present an optically tunable feedback field-effect transistor (FBFET) with two independent gates and a p+-i-n+ silicon nanowire. Because of the feedback operation, the FBFET features extremely steep switching characteristics with subthreshold swings <4 mV dec−1, and it can be reconfigured as a p- or n-type transistor by controlling the gate-voltage biases. When the FBFET is exposed to a He–Ne laser beam (λ = 633 nm), photogenerated carriers accumulate in the potential wells and reduce the potential-barrier height. The optically tunable feedback operation is attributed to the lowering of the potential barrier caused by the light. The triggering voltages can be modulated according to illumination, even when feedback is being provided. This optically tunable transistor with excellent switching characteristics opens up possibilities for application in future optoelectronic devices. [ABSTRACT FROM AUTHOR]

Omega-shaped-gate (OSG) nanowire-based field effect transistors (FETs) have attracted a great deal of attention recently, because theoretical simulations predicted that they should have a higher device performance than nanowire-based FETs with other gate geometries. OSG FETs with channels composed of ZnO nanowires were successfully fabricated in this study using photolithographic processes. In the OSG FETs fabricated on oxidized Si substrates, the channels composed of ZnO nanowires with diameters of about 110 nm are coated with Al2O3 using atomic layer deposition, which surrounds the channels and acts as a gate dielectric. About 80% of the surfaces of the nanowires coated with Al2O3 are covered with the gate metal to form OSG FETs. A representative OSG FET fabricated in this study exhibits a mobility of 30.2 cm2/ (V s), a peak transconductance of 0.4 μS (Vg = −2.2 V), and an Ion/Ioff ratio of 107. To the best of our knowledge, the value of the Ion/Ioff ratio obtained from this OSG FET is higher than that of any of the previously reported nanowire-based FETs. Its mobility, peak transconductance, and Ion/Ioff ratio are remarkably enhanced by 3.5, 32, and 106 times, respectively, compared with a back-gate FET with the same ZnO nanowire channel as utilized in the OSG FET. [ABSTRACT FROM AUTHOR]

Inthis study, we present the steep switching characteristics of bendablefeedback field-effect transistors (FBFETs) consisting of p–i–n nanowires (NWs) and dual-top-gatestructures. As a result of a positive feedback loop in the intrinsicchannel region, our FBFET features the outstanding switching characteristicsof an on/off current ratio of approximately 106, and pointsubthreshold swings (SSs) of 18–19 mV/dec in the n-channeloperation mode and of 10–23 mV/dec in the p-channel operationmode. Not only can these devices operate in n- or p-channel modes,their switching characteristics can also be modulated by adjustingthe gate biases. Moreover, the device maintains its steep SS characteristics,even when the substrate is bent. This study demonstrates the promisingpotential of bendable NW FBFETs for use as low-power components inintegrated circuits or memory devices. [ABSTRACT FROM AUTHOR]