Hui Xiao

Oxide Electric-Double-Layer Transistors Gated by a Chitosan-Based Biopolymer Electrolyte

Indium-zinc-oxide (IZO) electric-double-layer transistors are fabricated on proton conducting chitosan-based biopolymer electrolyte. Due to the extremely strong proton gating originated from proton migration within the chitosan films, good electrical performances are obtained. Characteristic time for the proton gating is estimated to be on the order of several milliseconds. Furthermore, a resistor loaded inverter is built, showing a high-voltage gain of ~9 at a low supply voltage of 1.2 V. The proton-gated IZO transistors may find potential applications in portable electronics and synaptic electronics.

Transient Characteristics for Proton Gating in Laterally Coupled Indium–Zinc-Oxide Transistors

The control and detection over processing, transport and delivery of chemical species is of great importance in sensors and biological systems. The transient characteristics of the migration of chemical species reflect the basic properties in the processings of chemical species. Here, we observed the field-configurable proton effects in a laterally coupled transistor gated by phosphorosilicate glass (PSG). The bias on the lateral gate would modulate the interplay between protons and electrons at the PSG/indium-zinc-oxide (IZO) channel interface. Due to the modulation of protons flux within the PSG films, the IZO channel current would be modified correspondingly. The characteristic time for the proton gating is estimated to be on the order of 20 ms. Such laterally coupled oxide based transistors with proton gating are promising for low-cost portable biosensors and neuromorphic system applications.

Lateral protonic/electronic hybrid oxide thin-film transistor gated by SiO2 nanogranular films

Ionic/electronic interaction offers an additional dimension in the recent advancements of condensed materials. Here, lateral gate control of conductivities of indium-zinc-oxide (IZO) films is reported. An electric-double-layer (EDL) transistor configuration was utilized with a phosphorous-doped SiO2 nanogranular film to provide a strong lateral electric field. Due to the strong lateral protonic/electronic interfacial coupling effect, the IZO EDL transistor could operate at a low-voltage of 1u2009V. A resistor-loaded inverter is built, showing a high voltage gain of ∼8 at a low supply voltage of 1u2009V. The lateral ionic/electronic coupling effects are interesting for bioelectronics and portable electronics.

Multi-gate synergic modulation in laterally coupled synaptic transistors

Laterally coupled oxide-based synaptic transistors with multiple gates are fabricated on phosphorosilicate glass electrolyte films. Electrical performance of the transistor can be evidently improved when the device is operated in a tri-gate synergic modulation mode. Excitatory post-synaptic current and paired pulse facilitation (PPF) behavior of biological synapses are mimicked, and PPF index can be effectively tuned by the voltage applied on the modulatory terminal. At last, superlinear to sublinear synaptic integration regulation is also mimicked by applying a modulatory pulse on the third modulatory terminal. The multi-gate oxide-based synaptic transistors may find potential applications in biochemical sensors and neuromorphic systems.

Flexible Proton-Gated Oxide Synaptic Transistors on Si Membrane

Ion-conducting materials have received considerable attention for their applications in fuel cells, electrochemical devices, and sensors. Here, flexible indium zinc oxide (InZnO) synaptic transistors with multiple presynaptic inputs gated by proton-conducting phosphorosilicate glass-based electrolyte films are fabricated on ultrathin Si membranes. Transient characteristics of the proton gated InZnO synaptic transistors are investigated, indicating stable proton-gating behaviors. Short-term synaptic plasticities are mimicked on the proposed proton-gated synaptic transistors. Furthermore, synaptic integration regulations are mimicked on the proposed synaptic transistor networks. Spiking logic modulations are realized based on the transition between superlinear and sublinear synaptic integration. The multigates coupled flexible proton-gated oxide synaptic transistors may be interesting for neuroinspired platforms with sophisticated spatiotemporal information processing.

Extended-gate-type IGZO electric-double-layer TFT immunosensor with high sensitivity and low operation voltage

An immunosensor is proposed based on the indium-gallium-zinc-oxide (IGZO) electric-double-layer thin-film transistor (EDL TFT) with a separating extended gate. The IGZO EDL TFT has a field-effect mobility of 24.5u2009cm2u2009V−1u2009s−1 and an operation voltage less than 1.5u2009V. The sensors exhibit the linear current response to label-free target immune molecule in the concentrations ranging from 1.6 to 368u2009×u200910−15u2009g/ml with a detection limit of 1.6u2009×u200910−15u2009g/ml (0.01 fM) under an ultralow operation voltage of 0.5u2009V. The IGZO TFT component demonstrates a consecutive assay stability and recyclability due to the unique structure with the separating extended gate. With the excellent electrical properties and the potential for plug-in-card-type multifunctional sensing, extended-gate-type IGZO EDL TFTs can be promising candidates for the development of a label-free biosensor for public health applications.

Protonic/electronic hybrid oxide transistor gated by chitosan and its full-swing low voltage inverter applications

Modulation of charge carrier density in condensed materials based on ionic/electronic interaction has attracted much attention. Here, protonic/electronic hybrid indium-zinc-oxide (IZO) transistors gated by chitosan based electrolyte were obtained. The chitosan-based electrolyte illustrates a high proton conductivity and an extremely strong proton gating behavior. The transistor illustrates good electrical performances at a low operating voltage of ∼1.0u2009V such as on/off ratio of ∼3u2009×u2009107, subthreshold swing of ∼65u2009mV/dec, threshold voltage of ∼0.3u2009V, and mobility of ∼7u2009cm2/Vu2009s. Good positive gate bias stress stabilities are obtained. Furthermore, a low voltage driven resistor-loaded inverter was built by using an IZO transistor in series with a load resistor, exhibiting a linear relationship between the voltage gain and the supplied voltage. The inverter is also used for decreasing noises of input signals. The protonic/electronic hybrid IZO transistors have potential applications in biochemical sensors and...

Hodgkin-Huxley Artificial Synaptic Membrane Based on Protonic/Electronic Hybrid Neuromorphic Transistors

Iontronics is a newly emerging interdisciplinary concept that bridges electronics and ionics. It provides new opportunities for biomimic information processing. Iontronic devices can act as building blocks for neuromorphic platforms. Here, a proof‐of‐principle Hodgkin–Huxley artificial synaptic membrane is proposed for the first time based on inorganic proton conductor. Phosphosilicate glass‐based proton conductor electrolyte demonstrates unique short‐term volatile charging behaviors, indicating potential short‐term synaptic plasticity applications. By using protonic/electronic hybrid oxide transistor configuration, dynamic synaptic membrane potential responses are triggered with gate current spikes. Typical resting potential, excitatory/inhibitory postsynaptic potential behaviors, and membrane depolarization/activation behaviors are mimicked on the proposed Hodgkin–Huxley artificial synaptic membrane. Moreover, proton‐related electrostatic coupling enables the device to possess short‐term synaptic plasticities with low power consumption. The proposed Hodgkin–Huxley artificial synaptic membrane provides a new prototype for neuromorphic system applications.

Paste-type thin-film transistors based on self-supported chitosan membranes

Chitosan is a most common biopolysaccharide and has been widely used for bio- or medical-materials. In this work, chitosan was prepared in the form of self-supported proton-conducting membranes with a high proton conductivity of 2.3 × 10−3 S cm−1 by protonic acid doping at room temperature. These chitosan-based self-supported membranes were then used as both flexible substrates and gate dielectrics for fabricating paste-type thin-film transistors (TFTs). The feature of these paste-type TFTs is that all the electrodes (gate/source/drain electrodes) and channels are located on the same one side of chitosan dielectric membranes, which is very convenient for TFTs to be transferred and stuck on various places in a wide variety of applications. Due to the huge lateral electric-double-layer (EDL) capacitive coupling induced by spatial movement of protons in chitosan-based proton-conducting membranes, these TFTs showed a low-voltage operation of only 1.5 V with a large field-effect mobility of 20.2 cm2 V−1 s−1. Furthermore, AND logic operation was also demonstrated on these TFTs. Our results indicate these chitosan-based paste-type TFTs have great potential for broadening their applications on wearable electronic products and biocompatible electronics.

Humidity-Dependent Synaptic Plasticity for Proton Gated Oxide Synaptic Transistor

Indium-tin-oxide synaptic transistors using proton conducting nanogranular phosphorosilicate glass as gate dielectric are fabricated. Humidity-dependent proton gating behaviors are observed. Moreover, synaptic plasticities are mimicked on the proton gated oxide synaptic transistors. Interestingly, enhanced synaptic facilitation is observed at higher relative humidity originated from the strengthened proton gating. An oxide synaptic transistor with humidity-dependent synaptic plasticities may find potential applications in neuromorphic platforms.