Electric Double Layer Transistors Based on 2-D Electron Gases Operated at a Low Voltage for Synaptic Devices

Low-voltage-operated electric double layer transistor (EDLT) for synaptic devices are fabricated by leveraging the 2-D electron gases (2DEGs) formed at interfaces LaAlO3/KTaO3 (LAO/KTO) and LAO/SrTiO3 (STO) at room temperature (RT). The EDLT devices demonstrate promising characteristics, including a high ON/OFF-state current ratio of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.0\times 10^{{6}}$ </tex-math></inline-formula> and a low subthreshold swing (SS) of 138.9 mV/dec upon a low sweeping gate voltage (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\text {g}}$ </tex-math></inline-formula>) from -1 to 2.5 V. The characteristics are comparable to those of 2DEGs-based field-effect transistors prepared at higher temperatures (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\ge 500~^{\circ }$ </tex-math></inline-formula> C). By harnessing the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\text {g}}$ </tex-math></inline-formula>-induced ions migration, we successfully develop the 2DEGs-based synaptic device capable of emulating neuromorphic features, including paired-pulse facilitation and filtering functionality. This research not only expands the range of room-temperature applications for 2DEGs in field-effect transistors (FETs), but also presents a viable approach to design 2DEGs-based synaptic devices for neuromorphic computing.