“The 2D hybrid metal halide-based device used here is smaller and more economical to produce, is robust and works well at higher temperatures. This suggests that 2D hybrid metal halide materials may prove superior to the current conventional semiconductor materials for THz applications.”Dali Sun, North Carolina State University
Researchers have utilized two-dimensional (2D) hybrid metal halides in a device that allows directional control of terahertz radiation generated by a spintronic scheme. The device has better signal efficiency than conventional terahertz generators, and is thinner, lighter and less expensive to produce.
Terahertz (THz) refers to the part of the electromagnetic spectrum between microwave and optical (i.e., frequencies between 100GHz and 10THz), and THz technologies have shown promise for applications ranging from faster computing and communications to sensitive detection equipment. However, creating reliable THz devices has proved challenging due to their size, cost and energy conversion inefficiency.
“Ideally, THz devices of the future should be lightweight, low-cost and robust, but that has been difficult to achieve with current materials,” says Dali Sun, assistant professor of physics at North Carolina State University and co-corresponding author of a paper on this work in Nature Communications. “In this work, we found that a 2D hybrid metal halide commonly used in solar cells and diodes, in conjunction with spintronics, may meet several of these requirements.”
The 2D hybrid metal halide in question is a popular and commercially available synthetic hybrid semiconductor: butyl ammonium lead iodine. Spintronics refers to controlling the spin of an electron, rather than just using its charge, in order to create energy.
Sun and colleagues from Argonne National Laboratories, the University of North Carolina at Chapel Hill and Oakland University created a device that layered the 2D hybrid metal halide with a ferromagnetic metal. They then excited this device with a laser, creating an ultrafast spin current that in turn generated THz radiation.
Not only did this 2D hybrid metal halide device outperform larger, heavier and more expensive THz emitters currently in use, but the researchers found that the 2D hybrid metal halide’s properties allowed them to control the direction of the THz transmission.
“Traditional terahertz transmitters were based upon ultrafast photocurrent,” Sun says. “But spintronic-generated emissions produce a wider bandwidth of THz frequency, and the direction of the THz emission can be controlled by modifying the speed of the laser pulse and the direction of the magnetic field, which in turn affects the interaction of magnons, photons and spins, and allows us directional control.”
Sun believes this work could be a first step in exploring 2D hybrid metal halide materials for potential use in a range of spintronic applications.
“The 2D hybrid metal halide-based device used here is smaller and more economical to produce, is robust and works well at higher temperatures,” Sun says. “This suggests that 2D hybrid metal halide materials may prove superior to the current conventional semiconductor materials for THz applications, which require sophisticated deposition approaches that are more susceptible to defects.
“We hope that our research will launch a promising testbed for designing a wide variety of low-dimensional hybrid metal halide materials for future solution-based spintronic and spin-optoelectronic applications.”
This story is adapted from material from North Carolina State University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.