A Dual‐Gate InGaZnO₄‐Based Thin‐Film Transistor for High‐Sensitivity UV Detection

Abstract

produces some real risks, including wrinkles, pigmented flat spots known as liver spots, and even skin cancer. [1][2][3][4] These are mostly attributed to the effects of UV light, a shorter wavelength than the visual spectrum. Therefore, over the past decades, developments in UV sensors have received significant attention for their potential positive effects on human health.When considering the performance of many different UV sensors, required features include high sensitivity, stability, and linearity. Most importantly, a compact design compatible with current device fabrication process is key for low-cost production. [5,6] Previous studies mostly focused on a two terminal photodiode device based on wide bandgap (WBG) semiconductor materials such as TiO 2 , SiC, and ZnO materials. [7][8][9] Later, some III-V compounds, such as gallium nitride (GaN), also received attention as UV photodetector materials. [10,11] Some metal-semiconductor-metal (MSM) structures have also been proposed to simplify device fabrication processes. [7][8][9][10][11][12] Although such WBG-based UV sensors have the advantages of a simple structure and high intrinsic visible-blindness; numinous drawbacks such as poor crystal quality or high activation energy of dopants have slowed developments. In addition, UV-sensing devices have received significant recent attention for applications in areas such as human health, fire detection, and optical communication.One key factor for product commercialization is determining the optimal materials that allow for integration of excellent UV-sensing properties with compatibility with industrial fabrication processes. However, current UV sensors often fail to achieve this due to either mismatched materials or a device that must be excessively large in order to produce enough photocurrent for UV detection. The UV-light-sensing properties of an amorphous InGaZnO 4 (IGZO) thin-film transistor with a dual-gate structure and relatively small device size (width/length = 50 μm/10 μm) that achieves high sensitivity through a threshold-voltage-(V th )-adjustment method is proposed. Comparing the drain currents under UV exposure to those under darkened conditions indicates that the ratio between the photoinduced and dark current reaches 10 6 . Furthermore, the UV sensitivity of the dual-gate transistors can be adjusted by varying the bottom gate voltage, with each pixel of the sensor then being read out separately via scan line pulses. This allows the dual-gate a-IGZO transistor to be used for high-performance UV sensing while being effectively integrated in display applications. SensorsAlmost all living things on Earth rely on the sun for nutrition and survival, whether directly or indirectly. The sun provides radiant heat, and gives energy to plants for the photosynthesis process, thus providing basic needs and food for creatures and humans. However, exposure to the sun for human beings also

Enhanced Electrical Performance and Bias‐Stress Stability of Solution‐Processed Bilayer Metal Oxide Thin‐Film Transistors

“…AOS film is usually prepared by magnetic sputtering or the solution‐processing method. [ 5–7 ] AOS films prepared by the sputtering technique have good uniformity, reproducibility, productivity but relatively high fabrication cost. In comparison, the solution‐processing technique is with the merits of low cost, large‐area compatibility, and potential low‐processing temperature on low‐cost flexible substrates.…”

Fabrication of graphene–ZnO heterostructure-based flexible and thin platform-based UV detector

“…Research focus in this direction is necessary as the graphene/ ZnO nanostructures provide better device performance by bringing in synergistic effects in electron transport as well as light absorption. Even though transistors are a compelling option towards development of UV detectors, they require complex fabrication processes and patterning for techniques to achieve required resolutions [15][16][17]. The advantage of using diode-based detector is that larger areas can be made available for UV detection, the sensitive area in a transistor-based sensor will be the channel or patterned gate which will have dimensions in the submicron range.…”

Spike Encoding with Optic Sensory Neurons Enable a Pulse Coupled Neural Network for Ultraviolet Image Segmentation

“…Next, in order to mimic the visual perception functionality of the human vision system, an IGZO 4 -based UV sensor was fabricated. − Figure a displays a schematic illustration of the UV sensor with a structure of Ta/IGZO 4 /Pt, where a beam of UV light was illuminated vertically on the device, and its photoresponse properties were investigated. The detailed parameters can be found in the experiment part.…”

“…Figure c illustrates the resistance state of the UV sensor in a dark environment and under UV illuminations with different wavelengths, including 365 nm, 254 nm, and simultaneous illuminations of both 365 and 254 nm. It can be clearly observed that the device resistance decreases as the wavelength decreases, which can be attributed to the interband transition and band-tail absorption of IGZO 4 films occurring in different light regions. − It should be noted that, instead of using light pulses, here we investigated the light-sensing performance of the device under a persistent light illumination, and electrical pulses were used to read out the device state, showing that the conductance of the Ta/IGZO 4 /Pt devices is indeed a function of the input UV light. Hence, the IGZO 4 -based UV sensor can be used as a receiver of UV signals for sensing and information communication.…”