Brain-inspired circuit board with glowing synapses and UV light.

Brain-Inspired Tech: Synaptic Transistors Mimic Learning with Light and Electricity

Elliot Brynn in Tech & Innovation December 2025 • 4 min read.

"New research explores how proton-gated transistors can replicate brain functions, opening doors to advanced AI and memory technologies."

Our brains are incredibly efficient at handling complex problems, a feat that still challenges modern computers. The secret lies in the vast network of neurons connected by biological synapses. Researchers are working hard to understand these synapses and replicate their functions in electronic devices. The goal? To create computers that are more like our brains – capable of parallelism, structural plasticity, and robustness.

Traditional electronic devices like memristors and transistors are being adapted to mimic synaptic behavior. Synaptic transistors, in particular, offer a promising approach. These three-terminal devices can transmit signals through a semiconductor channel and simultaneously learn by adjusting the interaction between the channel and an insulating layer. This is closer to how our brains work compared to two-terminal devices.

Now, scientists are exploring the use of UV light to influence these synaptic transistors, drawing inspiration from studies showing that moderate UV exposure can enhance learning and memory in the brain. A new study combines a nanogranular silicon dioxide (SiO2) layer with an indium-gallium-zinc oxide (IGZO) channel in a synaptic transistor, demonstrating the potential of this approach for creating more brain-like computing systems.

How Does This Synaptic Transistor Work?

Brain-inspired circuit board with glowing synapses and UV light.

The key to this innovation is the use of amorphous indium-gallium-zinc oxide (a-IGZO) as the channel material, combined with nanogranular SiO2 as the gate oxide. This combination allows the transistor to mimic the short-term plasticity and short-term memory functions of a biological synapse. The device operates at low energy consumption, around 1.08 picojoules per pulse, and at voltages within 100 mV.

The device's behavior is explained by the movement of protons within the insulating layer. These protons respond to electrical and light stimuli, influencing the flow of current through the IGZO channel. This movement creates changes in the transistor's conductivity, similar to how synapses in the brain strengthen or weaken their connections.

Here's a breakdown of the key findings:

Electrical Stimulus: The transistor exhibits both short-term potentiation (STP) and short-term depression (STD), meaning its response to a stimulus can either increase or decrease over time.
Pulse Number: The amplitude of the excitatory postsynaptic current (EPSC) changes with the number of pulses, following a saturating exponential function.
UV Light Influence: The UV light's frequency has a significant effect on the synapse's plasticity, promoting paired-pulse facilitation (PPF) and enhancing the EPSC gain. Other parameters like intensity and duration have less impact.

Interestingly, the researchers found that the frequency of the light pulses had a more significant impact on the synapse's plasticity than other light pulse parameters, including intensity, number, and width. This suggests that the transistor is particularly sensitive to the rhythm of incoming light signals.

The Future of Brain-Like Computing

This research demonstrates the potential of proton-gated synaptic transistors for mimicking the brain's learning and memory functions. By combining electrical and light stimuli, these devices offer a new approach to creating more efficient and sophisticated AI systems.

While challenges remain in fabricating complex synaptic transistor networks, this work paves the way for future research in areas like multi-presynaptic inputs and organic wearable insulators. The nanogranular SiO2/IGZO structure offers a promising platform for advancing synaptic electronics.

Ultimately, this research brings us closer to a future where computers can learn, adapt, and solve problems more like our own brains. It's a significant step towards truly intelligent machines.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1109/jeds.2018.2875976, Alternate LINK

Title: Proton Conductor Gated Synaptic Transistor Based On Transparent Igzo For Realizing Electrical And Uv Light Stimulus

Subject: Electrical and Electronic Engineering

Journal: IEEE Journal of the Electron Devices Society

Publisher: Institute of Electrical and Electronics Engineers (IEEE)

Authors: Weijun Cheng, Renrong Liang, He Tian, Chuanchuan Sun, Chunsheng Jiang, Xiawa Wang, Jing Wang, Tian-Ling Ren, Jun Xu

Published: 2019-01-01

Everything You Need To Know

What exactly is a synaptic transistor?

A synaptic transistor is a device designed to mimic the function of a biological synapse in the brain. This specific type of synaptic transistor utilizes both electrical and UV light stimuli to replicate the brain's ability to learn and remember. It consists of a nanogranular silicon dioxide (SiO2) layer and an indium-gallium-zinc oxide (IGZO) channel. The transistor's behavior is determined by the movement of protons within the insulating layer, responding to both electrical and light stimuli, which affects the flow of current through the IGZO channel.

Why is UV light used in these synaptic transistors?

The use of UV light in synaptic transistors is significant because it mimics how the brain processes information and enhances learning. Scientists have observed that exposure to moderate UV light can improve learning and memory. In this research, the frequency of UV light pulses was found to have a significant impact on the plasticity of the synaptic transistor, promoting paired-pulse facilitation and enhancing the excitatory postsynaptic current (EPSC). This suggests a new approach to creating more efficient and sophisticated AI systems inspired by the brain.

What is the importance of the IGZO channel and SiO2 gate oxide in this design?

The IGZO channel and the SiO2 gate oxide combination is critical because it allows the synaptic transistor to replicate the short-term plasticity and short-term memory functions of a biological synapse. The IGZO channel acts as the pathway for electrical signals, while the SiO2 gate oxide, with its nanogranular structure, controls the flow of current. This setup enables the device to respond to both electrical and light stimuli, changing its conductivity. The interplay between these components allows the synaptic transistor to function similarly to how synapses in the brain strengthen or weaken their connections, enabling it to learn and remember.

Why is this research important?

This innovation is important because it offers a pathway to create more efficient and sophisticated AI systems. Traditional computers struggle with complex problems that the brain handles with ease, such as parallelism and structural plasticity. The synaptic transistor addresses these limitations by mimicking the brain's structure and function. By combining electrical and light stimuli, this approach offers a novel method for designing computers that can learn, adapt, and process information in a more brain-like manner, potentially leading to advanced AI applications.

What do short-term potentiation (STP) and short-term depression (STD) mean in the context of this synaptic transistor?

Short-term potentiation (STP) and short-term depression (STD) are key behaviors exhibited by the synaptic transistor, mirroring the dynamic responses of biological synapses. STP and STD refer to the ability of the transistor's response to increase or decrease over time in response to a stimulus. The amplitude of the excitatory postsynaptic current (EPSC) changes with the number of pulses, following a saturating exponential function. The UV light's frequency influences the synapse's plasticity, promoting paired-pulse facilitation (PPF) and enhancing the EPSC gain. These characteristics are crucial for replicating how the brain's synapses adjust their strength, which is essential for learning and memory.