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Ultraviolet photodetectors (UVPDs) based on diode-connected In-Ga-ZnO (IGZO) thin-film transistors (TFTs), called field-effect diodes (FEDs), are presented. A patterned NiO capping layer (CL) deposited on the top surface of the IGZO channel forming a heterojunction (HJ) was employed to further improve UV detection performance. Experimental results show that FED-based UVPDs have advantages over traditional TFT-based UVPDs, achieving a minimum dark current without additional gate bias and a wider bias range for detection measurements. UVPDs based on the 30-nm-thick IGZO FED with NiO CL show a photoresponsivity and photosensitivity of up to 1376 A/W and $9.10\times10$ 7 A/A at 275 nm under ${V} _{D}$ = −1.5 V, which is about $25\times $ and $1480\times $ higher than the case without NiO CL. These improvements are due to the fact that the NiO CL/IGZO HJ reduces the effective channel thickness to suppress dark current and provide additional optically generated electrons in the channel and an additional negative threshold voltage shift to enhance the photocurrent. [ABSTRACT FROM AUTHOR]

A physical assessment of the lateral gate-all-around (GAA) nanosheet transistor (NSFET) at the G40M16 node (gate length = 12 nm projected for 2028) of the newly defined beyond-Moore International Roadmap for Devices and Systems [~5 nm node of the predecessor International Technology Roadmap for Semiconductors (ITRS)], supported by 3-D numerical device simulations and based on a proposed per-footprint scheme, is presented. The traditional evaluation scheme to gauge the performance of the transistor “per effective channel width” is shown to be improper due to pervasive bulk inversion. Bulk inversion, along the width of the nanosheet and at its ends, obfuscates the dependence of current on sheet/channel width and undermines the presumed added benefit of short-channel effect (SCE) control in the GAA device. The NSFET provides a flexible sheet width, as opposed to that of the FinFET with discrete fins, but the allowed range of sheet width is limited due to significant parasitic capacitance at a relatively narrow width and degraded SCE control and increased resistance for desired wide width. Furthermore, the nanosheet (NS) device density is undermined at a narrow width, especially for decreasing pitch. The FinFET is shown to be a favorable alternative to the NSFET even at the G40M16 node. [ABSTRACT FROM AUTHOR]

Affective computing is one of the key technologies to achieve advanced brain-machine interfacing. It is increasingly concerning research orientation in the field of artificial intelligence. Emotion recognition is closely related to affective computing. Although emotion recognition based on electroencephalogram (EEG) has attracted more and more attention at home and abroad, subject-independent emotion recognition still faces enormous challenges. We proposed a subject-independent emotion recognition algorithm based on dynamic empirical convolutional neural network (DECNN) in view of the challenges. Combining the advantages of empirical mode decomposition (EMD) and differential entropy (DE), we proposed a dynamic differential entropy (DDE) algorithm to extract the features of EEG signals. After that, the extracted DDE features were classified by convolutional neural networks (CNN). Finally, the proposed algorithm is verified on SJTU Emotion EEG Dataset (SEED). In addition, we discuss the brain area closely related to emotion and design the best profile of electrode placements to reduce the calculation and complexity. Experimental results show that the accuracy of this algorithm is 3.53 percent higher than that of the state-of-the-art emotion recognition methods. What's more, we studied the key electrodes for EEG emotion recognition, which is of guiding significance for the development of wearable EEG devices. [ABSTRACT FROM AUTHOR]

A planar angled-dipole antenna is investigated in this communication. The angled dipole has an intersection angle of 60°, radiating quasi-isotropic pattern with a gain difference of about 6.4 dB over the entire spherical radiating surface. To improve the isotropy of the antenna, two near-field parasitic elements (NFPEs) are further introduced. The NFPEs function as supplementary radiators and they help to enhance the radiation in the weak region, decreasing the gain difference significantly to 1.57 dB. For demonstration, a prototype operating at 2.4 GHz is fabricated and measured. The prototype shows a high efficiency of 90%, and the roundness is less than 2.59 dB across the entire impedance passband (2376–2526 MHz). [ABSTRACT FROM AUTHOR]

As the most critical component of wireless power transfer (WPT) and wireless energy harvesting (WEH) systems, the rectifier is required to exhibit excellent performance. Most existing works focus on improvement in efficiency and bandwidth for a given input power level. However, in practice, the input power level is usually unpredictable. Therefore, a rectifier which exhibits high efficiency over a wide range of input power is highly desirable. But existing structures can only achieve limited input power range with a complex configuration. A novel cooperative structure using two diodes with diverse characteristics is proposed to solve these problems. Theoretical analysis and a comparison of performances with conventional ones are carried out. For validation in different application scenarios, two rectifiers operating at 2.4 GHz were designed, fabricated, and measured. For the proposed rectifier I, the measured efficiency is larger than 60% over an input power range from 3.5 to 25.2 dBm. While for rectifier II, the measured efficiency remains over 50% with input power from −6 to 26.5 dBm. These results demonstrated the effectiveness of the proposed structure in extending the input power range, especially for the low power region. Furthermore, the application in a WPT system was also demonstrated. [ABSTRACT FROM AUTHOR]

A high power oscillation occurring on a porous silicon diode with an obvious dc N-shaped negative differential resistance (NDR) at room temperature is presented for the first time. The voltage oscillation swing was up to 12.4 V and oscillation frequency was 101.3 kHz, which belongs to the radio frequency range. The oscillation was based on a porous silicon superlattice diode structure, which was observed to provide a stable NDR with a high peak-to-valley current ratio as high as 7.9 for dc current–voltage characteristics at room temperature. A superlattice diode structure was formed by an electrochemical etching method on an n-type (100) silicon wafer with an alternating etching current. In addition, a dc constant current source was used as the power supply for the diode oscillation. In particular, two steady operating points were observed for the dc NDR current–voltage characteristics of the circuit load line. The system produced a steady oscillation between these two operating points in a harmonic form. [ABSTRACT FROM PUBLISHER]

This study is the first to investigate different reliability mechanisms of high-performance low-temperature polycrystalline silicon thin-film transistors (TFTs) with a \ HfO2 gate dielectric before and after dual plasma treatment (DPT) under various bias temperature instability (BTI) stresses. DPT samples under positive bias temperature instability (PBI) and negative bias temperature instability (NBI) stresses exhibited different degradation phenomena because of the negative polarity trapped oxide charges and positive fixed oxide charges (Si+), respectively. In addition, experimental data exhibited better reliability immunity for PBI stress than NBI stress after DPT. Furthermore, we raised the temperature to clearly observe the effect of the PBTI stress analysis for samples with and without DPT. Extracted measurement results showed distinct time evolutions of the interface state densities (Nit) for samples with and without DPT, revealing the different mechanisms of Nit generation with and without DPT. Finally, we proposed a novel reliability mechanism called the quasi reaction-diffusion model to explain the generation of \Delta\ Nit, which also explains the unclear phenomena of mobility boost. [ABSTRACT FROM PUBLISHER]