27 October 2020
Reversible programming for 2D semiconductors
Published online 29 September 2020
The temperature-induced transition of silver iodide into a ‘superionic’ state allows reversible manipulation of a single-layer semiconductor.
A layer of silver iodide can be used to reversibly create functional electronic components in an interacting semiconductor made of a single layer of bonded atoms. The unique electronic behaviour of single atomic layer (2D) semiconductors offers many opportunities in nanoscale electronics, but controlling their properties has been challenging.
Researchers at the University of California, Los Angeles (UCLA) achieved a new and remote form of control. It uses increased temperature to induce silver iodide to undergo a sharp transition into a ‘superionic state’ in which it becomes highly conductive to ions.
“The superionic property allows us to manipulate silver ions to build up a variety of ionic concentration profiles inside the silver iodide layer,” explains UCLA molecular scientist Xiangfeng Duan.
These structures in the silver iodide can be used to transfer electrical influences into an interacting layer of the semiconductor tungsten diselenide. This subtle means of remotely influencing semiconductors is known as electrostatic doping.
The researchers have demonstrated that their technique can create a variety of transistors, diodes and logic gates in the semiconductor, as required for microelectronic operations. Imran Shakir of King Saud University in Saudi Arabia contributed insights to assist the research.
A great advantage of the technique is that the programmed semiconductor features can be readily deleted by an increase in temperature or with ultraviolet light. Duan points out that this could be invaluable for use in security-sensitive applications, such as in the defence industry, or wherever it may be important to keep microelectronic systems secure.
Lee, S.-J. et al. Programmable devices based on reversible solid-state doping of two-dimensional semiconductors with superionic silver iodide. Nat. Electron. https://doi.org/10.1038/s41928-020-00472-x (2020).