In the applications such as food production, the environmental temperature should be measured continuously during the entire process, which requires an ultra-low-power temperature sensor for long-termly monitoring. Conventional temperature sensors trade the measurement accuracy with power consumption. In this work, we present a battery-free wireless temperature sensing chip for long-termly monitoring during food production. A calibrated oscillator-based CMOS temperature sensor is proposed instead of the ADC-based power-hungry circuits in conventional works. In addition, the sensor chip can harvest the power transferred by a remote reader to eliminate the use of battery. Meanwhile, the system conducts wireless bidirectional communication between the sensor chip and reader. In this way, the temperature sensor can realize both a high precision and battery-free operation. The temperature sensing chip is fabricated in 55 nm CMOS process, and the reader chip is implemented in 65 nm CMOS technology. Experimental results show that the temperature measurement error achieves ±1.6 °C from 25 to 50 °C, with battery-free readout by a remote reader.

In this work, the incorporation of Tantalum (Ta) into p-type metal-oxide (SnO_x) semiconductor film is investigated to improve the electrical characteristics and suppress the fringe effect of thin film transistors (TFTs). The Ta-doped SnO_x (SnO_x:Ta) film is deposited by radio-frequency (RF) magnetron sputtering with a Sn:Ta (3at.%) target and thermally annealed at 270 °C for 30 mins. Here, we observe that the SnO_x:Ta film presents increased crystallinity, reduced defect density (3.25 × 10¹² cm⁻²eV⁻¹), and widened bandgap (1.98 eV), in comparison with the undoped SnO_x film. As a result, the SnO_x:Ta TFTs exhibit a lower off-state current (I_off), an improved on/off current ratio (2.17 × 10⁴), a remarkably decreased subthreshold swing (SS) by 41%, and enhanced device stability. Additionally, by introducing Ta dopants, the fringe effect as well as the impact of channel width-to-length ratio (W/L) on electrical performances of the p-type oxide TFTs can be effectively suppressed. These results shall contribute to further exploration and development of p-type SnO_x TFTs.

GaN diodes for high energy (64.8 MeV) proton detection were fabricated and investigated. A comparison of the performance of GaN diodes with different structures is presented, with a focus on sapphire and on GaN substrates, Schottky and pin diodes, and different active layer thicknesses. Pin diodes fabricated on a sapphire substrate are the best choice for a GaN proton detector working at 0 V bias. They are sensitive (minimum detectable proton beam <1 pA/cm²), linear as a function of proton current and fast (<1 s). High proton current sensitivity and high spatial resolution of GaN diodes can be exploited in the future for proton imaging of patients in proton therapy.

This paper presents a 4-level pulse amplitude modulation (PAM-4) distributed feedback (DFB) laser driver. The driver adopts a digital slicing architecture to achieve high linearity by adjusting the weights of three thermometer-coded main paths. An efficient-biased output stage structure is proposed to reduce power consumption while avoiding the degradation of output node bandwidth typically induced by parasitic capacitance in high-current bias path. A two-tap linear and nonlinear feed-forward equalizer (FFE) is implemented in the digital domain to extend bandwidth limitations and compensate for the dynamic nonlinearity of the DFB laser. The nonlinear FFE is realized at the cost of lower power consumption and smaller area by utilizing the simultaneity of low-speed parallel data. The chip is fabricated in 28 nm CMOS process. Measurement results indicate that, with a laser bias current of 40 mA, a modulation current of 20 mApp, and an operating rate of 32 Gb/s PAM-4, the overall power consumption of the chip is 372 mW, corresponding to an energy efficiency of 11.6 pJ/b.

All-inorganic CsPbBr₃ perovskite quantum dots (QDs) have attracted extensive attention in photoelectric detection for their excellent photoelectric properties and stability. However, the CsPbBr₃ quantum dot film exhibits a high non-radiative recombination rate, and the mismatch in energy levels with the carbon electrode weakens hole extraction efficiency. These reduces the device's performance. To improve this, a semiconductor photodetector based on fluorine-doped tin oxide (FTO)/dense titanium dioxide (c-TiO₂)/mesoporous titanium dioxide (m-TiO₂)/CsPbBr₃ QDs/CsPbBr_xI_3–x (x = 2, 1.5, 1) QDs/C structure was studied. By adjusting the Br^– : I^– ratio, the synthesized CsPbBr_xI_3–x (x = 2, 1.5, 1) QDs showed an adjustable band gap width of 2.284−2.394 eV. And forming a type II band structure with CsPbBr₃ QDs, which reduced the valence band offset between the active layer and the carbon electrode, this promoted carrier extraction and reduced non-radiative recombination rate. Compared with the original device (the photosensitive layer is CsPbBr₃ QDs), the performance of the photodetector based on the CsPbBr₃ QDs/CsPbBr₂I QDs heterostructure is significantly improved, the responsivity (R) increased by 73%, the specific detectivity rate (D^*) increased from 6.98 × 10¹² to 3.19 × 10¹³ Jones, the on/off ratio reached 10⁶. This study provides a new idea for the development of semiconductor tandem detectors.

This paper describes a 2D/3D vision chip with integrated sensing and processing capabilities. The 2D/3D vision chip architecture includes a 2D/3D image sensor and a programmable visual processor. In this architecture, we design a novel on-chip processing flow with die-to-die image transmission and low-latency fixed-point image processing. The vision chip achieves real-time end-to-end processing of convolutional neural networks (CNNs) and conventional image processing algorithms. Furthermore, an end-to-end 2D/3D vision system is built to exhibit the capacity of the vision chip. The vision system achieves real-timing applications under 2D and 3D scenes, such as human face detection (processing delay 10.2 ms) and depth map reconstruction (processing delay 4.1 ms). The frame rate of image acquisition, image process, and result display is larger than 30 fps.

In this work, we design and fabricate AlGaN/GaN-based Schottky barrier diodes (SBDs) on a silicon substrate with a trenched n⁺-GaN cap layer. With the developed physical models, we find that the n⁺-GaN cap layer provides more electrons into the AlGaN/GaN channel, which is further confirmed experimentally. When compared with the reference device, this increases the two-dimensional electron gas (2DEG) density by two times and leads to a reduced specific ON-resistance （R_on,sp）of ~2.4 mΩ·cm². We also adopt the trenched n⁺-GaN structure such that partial of the n⁺-GaN is removed by using dry etching process to eliminate the surface electrical conduction when the device is set in the off-state. To suppress the surface defects that are caused by the dry etching process, we also deposit Si₃N₄ layer prior to the deposition of field plate (FP), and we obtain a reduced leakage current of ~8 × 10⁻⁵ A·cm⁻² and breakdown voltage (BV) of 876 V. The Baliga’s figure of merit (BFOM) for the proposed structure is increased to ~319 MW·cm⁻². Our investigations also find that the pre-deposited Si₃N₄ layer helps suppress the electron capture and transport processes, which enables the reduced dynamic R_on,sp.

Low power consumption, high responsivity, and self-powering are key objectives for photoelectrochemical ultraviolet detectors. In this research, In-doped α-Ga₂O₃ nanowire arrays were fabricated on FTO substrates through a hydrothermal approach, with subsequent thermal annealing. These arrays were then used as photoanodes to construct a UV photodetector. In doping reduced the bandgap of α-Ga₂O₃, enhancing its absorption of UV light. Consequently, the In-doped α-Ga₂O₃ nanowire arrays exhibited excellent light detection performance. When irradiated by 255 nm deep ultraviolet light, they obtained a responsivity of 38.85 mA/W. Moreover, the detector's response and recovery times are 13 and 8 ms respectively. The In-doped α-Ga₂O₃ nanowire arrays exhibit a responsivity that is about three-fold higher than the undoped one. Due to its superior responsivity, the In-doped device was used to develop a photoelectric imaging system. This study demonstrates that doping α-Ga₂O₃ nanowires with indium is a potent approach for optimizing their photoelectrochemical performance, which also has significant potential for optoelectronic applications.

The event-based vision sensor (EVS), which can generate efficient spiking data streams by exclusively detecting motion, exemplifies neuromorphic vision methodologies. Generally, its inherent lack of texture features limits effectiveness in complex vision processing tasks, necessitating supplementary visual information. However, to date, no event-based hybrid vision solution has been developed that preserves the characteristics of complete spike data streams to support synchronous computation architectures based on spiking neural network (SNN). In this paper, we present a novel spike-based sensor with digitized pixels, which integrates the event detection structure with the pulse frequency modulation (PFM) circuit. This design enables the simultaneous output of spiking data that encodes both temporal changes and texture information. Fabricated in 180 nm process, the proposed sensor achieves a resolution of 128 × 128, a maximum event rate of 960 Meps, a grayscale framerate of 117.1 kfps, and a measured power consumption of 60.1 mW, which is suited for high-speed, low-latency, edge SNN-based vision computing systems.

Doping plays a pivotal role in enhancing the performance of organic semiconductors (OSCs) for advanced optoelectronic and thermoelectric applications. In this study, we systematically investigated the doping performance and applicability of the ionic dopant 4−isopropyl−4′−methyldiphenyliodonium tetrakis(penta−fluorophenyl−borate) (DPI−TPFB) as a p−dopant for OSCs. Using the p−type OSC PBBT−2T as a model system, we demonstrated that DPI−TPFB shows significant doping effect, as confirmed by ESR spectra, UV−vis−NIR absorption, and work function analysis, and enhances the electronic conductivity of PBBT−2T films by over four orders of magnitude. Furthermore, DPI−TPFB exhibited broad doping applicability, effectively doping various p−type OSCs and even imparting p−type characteristics to the n−type OSC N2200, transforming its intrinsic n−type behavior into p−type. The application of DPI−TPFB−doped PBBT−2T films in organic thermoelectric devices (OTEs) was also explored, achieving a power factor of approximately 10 μW∙m⁻¹∙K⁻². These findings highlight the potential of DPI−TPFB as a versatile and efficient dopant for integration into organic optoelectronic and thermoelectric devices.

Thermally chargeable supercapacitors (TCSCs) have unique advantages in the collection, conversion, and storage of thermal energy, contributing to the development of new strategies for thermal energy utilization. 2D MXene materials are predicted to be highly promising new thermoelectric materials. Here, we report a self-assembled flexible Ti₃C₂T_x MXene-based TCSC device, using prepared Ti₃C₂T_x MXene as the capacitor electrode and a NaClO₄/PEO gel as the electrolyte. We also explore the working mechanism of the TCSCs. The fabricated Ti₃C₂T_x-based TCSCs exhibit an excellent Seebeck coefficient of 11.8 mV∙K⁻¹ on average and maintain good cycling stability under various temperature differences. Demonstrations of multiple practical applications show that Ti₃C₂T_x MXene-based TCSC devices are excellent candidates for self-powered integrated electronic devices.

The dynamic avalanche effect is a critical factor influencing the performance and reliability of the field-stop insulated gate bipolar transistors (FS-IGBT). Unclamped inductive switching (UIS) is the primary method for testing the dynamic avalanche capability of FS-IGBTs. Numerous studies have demonstrated that factors such as device structure, avalanche-generating current filaments, and electrical parameters influence the dynamic avalanche effect of the FS-IGBT. However, few studies have focused on enhancing the avalanche reliability of the FS-IGBT by adjusting circuit parameters during operation. In this paper, the dynamic avalanche effect of the FS-IGBT under UIS conditions is comprehensively investigated through a series of comparative experiments with varying circuit parameters, including bus voltage V_DC, gate voltage V_G, gate resistance R_g, load inductance L, and temperature T_C. Furthermore, a method to enhance the dynamic avalanche reliability of the FS-IGBT under UIS by optimizing circuit parameters is proposed. In practical applications, reducing gate voltage, increasing load inductance, and lowering temperature can effectively improve the dynamic avalanche capability of the FS-IGBT.

AlGaN-based LEDs with peak wavelength below 240 nm (far-UVC) pose no significant harm to human health, thus highlighting their broader application potential. While, there is a significant Schottky barrier between the n-electrode and Al-rich n-AlGaN, adversely impeding electron injection and resulting in considerable heat generation. Here, we fabricate V-based electrodes of V/Al/Ti/Au on n-AlGaN with Al content over 80% and investigate the relationship between the metal diffusion and contact properties during the high-temperature annealing process. Experiments reveal that decreasing V thickness in the electrode promotes the diffusion of Al towards the surface of n-AlGaN, which facilitates the formation of V_N and thus the increase of local electron concentration, resulting in lower specific contact resistivity. Then, increasing the Al thickness inhibits the diffusion of Au to the n-AlGaN surface, suppressing the rise of Schottky barrier. Experimentally, an optimized n-electrode of V(10 nm)/Al(240 nm)/Ti(40 nm)/Au(50 nm) on n-Al_0.81Ga_0.19N is obtained, realizing an optimal specific contact resistivity of 7.30 × 10⁻⁴ Ω·cm². Based on the optimal n-electrode preparation scheme for Al-rich n-AlGaN, the work voltage of a far-UVC LED with peak wavelength of 233.5 nm is effectively reduced.