Lingyan Liang

Anti-ambipolar switches (AAS) are specialized field-effect devices tailored for ternary logic operations, presenting a viable solution to surpass the scaling constraints of traditional binary architectures. Here, we report a high-performance all-oxide AAS based on an indium-tin-zinc oxide/tin monoxide (SnO) heterojunction fabricated exclusively via CMOS-compatible processes. By systematically modulating the annealing conditions, we effectively engineer the defect states and carrier transport dynamics within the SnO channel to achieve exceptional switching characteristics. Consequently, the device exhibits a high peak-to-valley ratio (>102) over a narrow operational voltage range (0–8 V) and demonstrates excellent bias stability. To validate its practical utility, we construct a ternary logic inverter featuring well-defined intermediate logic states and a low power consumption of 3.29 μW. Ultimately, this research delineates a scalable and practical methodology for developing energy-efficient, multi-valued integrated circuits utilizing standard oxide semiconductor platforms.

Metal oxide thin-film transistors (MO TFTs) have drawn wide interest in photodetectors and optoelectronic synaptic devices owing to their wide bandgap, low off-state current, high optical transparency, low-temperature processing, and large-area uniformity. Gate modulation in the TFT structure can tune the channel’s initial state and interfacial electric field, enhancing the tunability of photogenerated carrier transport, defect trapping/release, and interfacial charge regulation. This article reviews the progress of MO TFT photodetectors and optoelectronic synaptic devices, and examines the roles of light absorption, carrier transport, defect-related carrier dynamics, interfacial charge control, and persistent photoconductivity in different device functions. For photodetectors, key goals include broadening the response spectrum, reducing dark current, improving spectral selectivity, and enhancing response stability. For optoelectronic synaptic devices, post-illumination conductance retention and slow relaxation enable memory retention and synaptic weight modulation. Thus, rather than being separate, photodetection and optoelectronic synapses are functional extensions of the MO TFT optoelectronic response under different application targets. This article further discusses the synergy between these two functions in array sensing, visual preprocessing, and intelligent vision systems. Future development requires advances in targeted defect engineering, interface and structure optimization, array uniformity, standardized evaluation, and device–circuit–algorithm co-design for low-power, integrable intelligent vision hardware.

In this work, InSnZnO (ITZO) thin films with different structural phases were obtained via Al-induced microstructure regularization (AIMR) method. The thin-film transistor (TFT) with amorphous front-channel and polycrystalline back-channel exhibits remarkable field-effect mobility ( μ FE ) boosted to 115.2 cm ² /Vs which is about twice that of the TFT with fully-crystallized channel. It is found that the partially-crystallized ITZO shows a denser microstructure with less oxygen vacancies (V _O ) in the front-channel region compared to the fully-crystallized one. Other electrical properties as well as the negative-bias-stress stability are also improved. TCAD simulations were performed to investigate the defect states in the channel, providing supportive evidence for the experimental results. Keeping the amorphous state and promoting its microstructure ordering to the utmost is a promising strategy to achieve high-mobility oxide TFTs.

In this Letter, we report a synergistic strategy combining Al-induced microstructure regulation (AIMR) and Al₂O₃ passivation layer by plasma-enhanced atomic layer deposition to overcome the mobility–stability trade-off in IGZO thin-film transistors (TFTs). The optimized device achieves a mobility of 72.75 cm²v^-1s^-1 and a threshold-voltage shift of 0.21 V under positive bias temperature stress (PBTS). This improvement arises from AIMR-induced transport regularization and passivation suppression of excessive oxygen-related defects. These results provide a practical route toward high-mobility and reliable oxide TFTs for AMOLED backplanes.

Amorphous gallium oxide thin-film transistor photodetectors are promising for ultraviolet detection because of their wide bandgap and low dark current. Magnetron sputtering is compatible with low-temperature processing, but device performance is sensitive to sputtering conditions. Poor parameter choices can introduce oxygen vacancies and interface charges, degrading optoelectronic performance. Here, a three-factor, three-level orthogonal design is used to vary sputtering power, Ar/O₂ flow ratio, and film thickness. Nine device sets are fabricated and compared based on transfer characteristics and transient photocurrent–time (I-t) responses measured at a wavelength of 254 nm, with clear differences observed among process combinations. To identify the origin of these differences, representative samples with significant responsivity variations were modeled using TCAD. By fitting the simulated I-t curves to measured transients, the interface fixed charge density and defect-state densities were extracted, and the photon absorption distribution of different samples was analyzed. This analysis, from both defect and UV absorption perspectives, revealed the reasons for the differences in responsivity. The absorption coefficients at 254 nm measured by ellipsometry for the two samples were also compared, and the absorption trends observed in both the simulation and ellipsometry were consistent, confirming the accuracy of the simulation results. This work presents an integrated experimental and TCAD approach for process optimization and mechanistic analysis of a-GaO_x TFT-PDs.

Oxide semiconductor-based neuromorphic devices hold great potential for visual information processing, yet their performance is critically limited by photolithography-induced organic residues. This work systematically investigates the effects of photoresist contaminants on In−Ga−Zn−O thin-film transistors (IGZO TFTs), revealing that these residues introduce deep-level trap states that degrade both photo-responsivity and carrier transport dynamics. Through optimized plasma-assisted surface treatments, these adverse effects would be effectively eliminated. Additionally, we show that gate−voltage modulation can precisely control the relaxation kinetics of photocarriers in these devices. By applying these strategies to IGZO-based synaptic arrays, we achieve enhanced image contrast through controlled optoelectronic response modulation. Overall, our findings highlight the critical impact of photolithography-induced organic residues in IGZO optoelectronic synaptic devices and demonstrate an effective approach for performance enhancement through surface plasma treatment and gate−voltage modulation.

This work analyzes carrier injection in SnO ambipolar thin-film transistors. The findings reveal that the surface states at the SnO surface would bring down the injection barrier, which can be modified by inserting an Al ₂ O ₃ thin film as a surface-modified layer. The addition of an Al ₂ O ₃ layer with a proper thickness raises the I _on / I _off ratios of both the n- and p- branches over 10 ³ without the tradeoff of other device properties. Moreover, a simple formula is proposed to correlate injection barrier variation with the off-current variation, which is subsequently verified using the experimental data.

As an ultrawide-bandgap semiconductor, gallium oxide (Ga₂O₃) exhibits intrinsic absorption characteristics in the solar-blind ultraviolet (SBUV) spectrum, holding immense potential for SBUV detection applications. However, achieving amorphous Ga₂O₃ photodetectors with simultaneously high responsivity and air stability remains a critical challenge. In this work, a strategy combining N-doping and low-temperature crystallization enhances both responsivity and air stability. An aluminum oxide (Al₂O₃) capping layer is introduced, which further acts as an effective optical modulation layer, enhancing the selectivity in the SBUV spectrum. Notably, compared to the control group, devices with an Al₂O₃ capping layer exhibited nanocrystalline structures in both the Al₂O₃ and channel layers, demonstrating superior performance, particularly an exceptional responsivity of 7.8 × 10⁵ A/W. The performance remains stable after being exposed to air for 100 days. These findings underscore the importance of microstructural engineering in oxide photodetector development, providing a concise and efficient technical pathway for advancing high-performance photodetectors and their industrial applications.