Artificial photonic synapses are emerging as a promising implementation to emulate the human visual cognitive system by consolidating a series of processes for sensing and memorizing visual information into one system. In particular, mimicking retinal functions such as multispectral color perception and controllable nonvolatility is important for realizing artificial visual systems. However, many studies to date have focused on monochromatic‐light‐based photonic synapses, and thus, the emulation of color discrimination capability remains an important challenge for visual intelligence. Here, an artificial multispectral color recognition system by employing heterojunction photosynaptic transistors consisting of ratio‐controllable mixed quantum dot (M‐QD) photoabsorbers and metal‐oxide semiconducting channels is proposed. The biological photoreceptor inspires M‐QD photoabsorbers with a precisely designed red (R), green (G), and blue (B)‐QD ratio, enabling full‐range visible color recognition with high photo‐to‐electric conversion efficiency. In addition, adjustable synaptic plasticity by modulating gate bias allows multiple nonvolatile‐to‐volatile memory conversion, leading to chromatic control in the artificial photonic synapse. To ensure the viability of the developed proof of concept, a 7 × 7 pixelated photonic synapse array capable of performing outstanding color image recognition based on adjustable wavelength‐dependent volatility conversion is demonstrated.

Solution processing of metal-oxide semiconductors has received significant attention in various fields of electronics owing to its advantages such as simple fabrication process, large-area scalability, and facile stoichiometric tunability. However, the conventional sol−gel route requires a relatively long annealing time to obtain a low-defect film with high density and sufficient amount of metal−oxygen−metal bonding state, which prevents implementation in cost-effective continuous manufacturing. Here, we report rapid formation of solution-processed oxide semiconductors by employing a dual-fuel-based solution combustion synthesis route. In particular, by optimizing the ratio of dual fuels of acetylacetone and 1,1,1trifluoro-acetylacetone (molar ratio of 7:3), high-performance indium−gallium−zinc oxide (IGZO) thin-film transistors (TFTs) could be fabricated at 350 °C with the annealing time as short as 5 min (In:Ga:Zn = 0.68:0.1:0.22). Based on spectroscopic analysis, it was found that the dual fuels enabled rapid formation of the metal−oxygen−metal lattice structure with low defective oxygen bonding states. The IGZO TFTs fabricated with an optimized fuel ratio exhibited average field-effect mobilities of 1.11 and 3.69 cm 2 V −1 s −1 with annealing times of 5 and 20 min, respectively (averaged in 9∼12 devices). Also, in the case of the 5 min annealed device, the threshold voltage was −0.48 ± 1.96 V, showing enhancement-mode operation. Furthermore, the device showed good stability against both positive gate bias stress and negative gate bias stress conditions with small threshold voltage shifts of −1.28 and − 1.28 V in 5760 s, respectively.

versus conventional amorphous silicon TFTs, as well as large area processability at low temperatures. [13][14][15][16] Furthermore, MOTFTs are less affected by short channel effects. [17][18][19] As in other transistor technologies, MOTFT performance strongly depends on the intrinsic semiconductor channel properties as well as the channel interfacial characteristics, including that of the top surface. [20][21][22] Furthermore, MOTFTs are limited by uncontrollable back channel trap densities, restricting their application in high-resolution displays, as well as 3D and virtual reality devices. [7,[23][24][25][26][27] Recently, several strategies were reported to enhance the performance of MOTFTs by adopting new device architectures, including dual gate implantation, [28][29][30] high-k insulators, [31][32][33] and semiconducting heterostructures. [34][35][36][37][38] Among these strategies, low-dimensional bi-or multilayer heterostructures of different MOs have enhanced the carrier mobility and drive current in MOTFTs. [39,40] These improvements typically originate from confined free electrons within the potential well of the heterointerface between two semiconductors having large Fermi energy differences. [41] However, although these approaches are noteworthy, limitations in available component materials and control of leakage currents have compromised the fidelity of this platform. [37,38] Another approach to enhance performance Thin-film transistors using metal oxide semiconductors are essential in many unconventional electronic devices. Nevertheless, further advances will be necessary to broaden their technological appeal. Here, a new strategy is reported to achieve high-performance solution-processed metal oxide thin-film transistors (MOTFTs) by introducing a metallic micro-island array (M-MIA) on top of the MO back channel, where the MO is a-IGZO (amorphous indium-gallium-zinc-oxide). Here Al-MIAs are fabricated using honeycomb cinnamate cellulose films, created by a scalable breath-figure method, as a shadow mask. For IGZO TFTs, the electron mobility (µ e ) increases from ≈3.6 cm 2 V −1 s −1 to near 15.6 cm 2 V −1 s −1 for optimal Al-MIA dimension/ coverage of 1.25 µm/51%. The Al-MIA IGZO TFT performance is superior to that of controls using compact/planar Al layers (Al-PL TFTs) and Au-MIAs with the same channel coverage. Kelvin probe force microscopy and technology computer-aided design simulations reveal that charge transfer occurs between the Al and the IGZO channel which is optimized for specific Al-MIA dimensions/surface channel coverages. Furthermore, such Al-MIA IGZO TFTs with a high-k fluoride-doped alumina dielectric exhibit a maximum µ e of >50.2 cm 2 V −1 s −1 . This is the first demonstration of a micro-structured MO semiconductor heterojunction with submicrometer resolution metallic arrays for enhanced transistor performance and broad applicability to other devices.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.202205871.

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