A breakthrough might contribute to the creation of new quantum or low-power semiconductors.
Illustration of redox gating for carrier manipulation and electric field control of the electronic state. The green threads represent functional molecules for redox gating, and the ability to function at low power mimics synaptic switching in the human brain, as represented by the underlying synapse. Image Credit: Argonne National Laboratory
The integrated circuits that drive electronics are becoming smaller and more powerful simultaneously. The trend of microelectronics has only picked up speed recently as researchers have attempted to cram more and more semiconducting components onto a single chip.
Because of their small size, microelectronics face a significant challenge. Microelectronics use a small portion of the electricity from conventional electronics to function at their best without overheating.
Scientists at the US Department of Energy’s (DOE) Argonne National Laboratory have made a breakthrough that could pave the way for a novel microelectronic material to fulfill this need. An innovative method of “redox gating” that regulates the flow of electrons into and out of semiconducting materials was presented by the Argonne team. The study was published in the journal Advanced Materials.
The subvolt regime, which is where this material operates, is of enormous interest to researchers looking to make circuits that act similarly to the human brain, which also operates with great energy efficiency.
Wei Chen, Materials Scientist and Study Co-Corresponding Author, Argonne National Laboratory
A chemical reaction that results in an electron transfer is referred to as “redox.” To function, microelectronic devices usually depend on an electric “field effect” to regulate the flow of electrons. By applying a voltage, or essentially a pressure that pushes electricity, across a material that served as a sort of electron gate, the scientists could control the flow of electrons from one end to the other in the experiment. The material would start injecting electrons through the gate from a source redox material into a channel material when the voltage reached a specific threshold or about half a volt.
The semiconducting device could function as a transistor, flipping between more conducting and more insulating states by adjusting the voltage to change the electron flow.
The new redox gating strategy allows us to modulate the electron flow by an enormous amount even at low voltages, offering much greater power efficiency. This also prevents damage to the system. We see that these materials can be cycled repeatedly with almost no degradation in performance.
Dillon Fong, Materials Scientist and Study Author, Argonne National Laboratory
Argonne materials scientist Wei Chen, one of the study’s co-corresponding authors, added, “Controlling the electronic properties of a material also has significant advantages for scientists seeking emergent properties beyond conventional devices. The subvolt regime, which is where this material operates, is of enormous interest to researchers looking to make circuits that act similarly to the human brain, which also operates with great energy efficiency.”
Hua Zhou, an Argonne physicist and another co-corresponding author of the study, suggested that the redox gating phenomenon might also help develop novel quantum materials whose phases could be controlled at low power. Furthermore, the redox gating method could be applied to low-dimensional quantum materials made of sustainable components as well as versatile functional semiconductors.
Research conducted at the DOE Office of Science user facility, Argonne’s Advanced Photon Source, contributed to characterizing redox gating behavior.
In addition, materials synthesis, device fabrication, and electrical measurements were performed at Argonne’s Center for Nanoscale Materials, a DOE Office of Science user facility.
The study was published on January 6th, 2024 in the journal Advanced Materials. Le Zhang, Changjiang Liu, Hui Cao, Andrew Erwin, Dillon Fong, Anand Bhattacharya, Luping Yu, Liliana Stan, Chongwen Zou, and Matthew V. Tirrell contributed to the study in addition to Fong, Chen and Zhou.
The study was funded by DOE’s Office of Science, Office of Basic Energy Sciences, and Argonne’s laboratory-directed research and development program.
Journal Reference:
Zhang, L., et al. (2024) Redox Gating for Colossal Carrier Modulation and Unique Phase Control. Advanced Materials. doi.org/10.1002/adma.202308871