To make artificial intelligence and autonomous driving systems more of a reality in everyday life, computer processors, that serve as the brain, must be able to analyze more data.
Operation results of the two-dimensional semiconductor device and logic device implemented by the joint research team. Image Credit: Korea Institute of Science and Technology (KIST)
Unfortunately, silicon-based logic devices, which are critical components of computer processors, have constraints in that processing costs and power consumption tends to increase as integration and miniaturization advance.
Electronic and logic devices built on very thin two-dimensional semiconductors at the atomic layer level are being studied to overcome these restrictions. In two-dimensional semiconductors, however, controlling electrical characteristics by doping is more challenging than in traditional silicon-based semiconductor devices.
As a result, implementing different logic devices with two-dimensional semiconductors has proved technically challenging.
The Korea Institute of Science and Technology (KIST) announced that a research team headed by Dr. Do Kyung Hwang of the Center for Opto-Electronic Materials and Devices and Professor Kimoon Lee of the Department of Physics at Kunsan National University has succeeded in developing two-dimensional semiconductor-based electronic and logic devices, whose electrical properties can be freely controlled by developing a novel ultra-thin electrode material, Cl-SnSe2.
Using Cl-doped tin diselenide (Cl-SnSe2), a two-dimensional electrode material, the collaborative research team was able to selectively regulate the electrical characteristics of semiconductor electronic devices.
Due to the Fermi-level pinning phenomenon, ordinary two-dimensional semiconductor devices only display the properties of either N-type or P-type devices, making complementary logic circuits difficult to design. By reducing flaws at the semiconductor interface and using the electrode material created by the collaborative research team, it is feasible to flexibly regulate the properties of N-type and P-type devices.
In other words, a single device may perform both N-type and P-type functions. As a result, the N-type and P-type devices do not need to be manufactured separately. The collaborative research team used this technology to create a high-performance, low-power complementary logic circuit that can execute various logic operations including NOR and NAND.
This development will contribute to accelerating the commercialization of next-generation system technologies such as artificial intelligence systems, which have been difficult to use in practical applications due to technical limitations caused by the miniaturization and high integration of conventional silicon semiconductor devices.
Dr. Do Kyung Hwang, Center for Opto-Electronic Materials and Devices, Korea Institute of Science and Technology
He added, “The developed two-dimensional electrode material is very thin; hence, they exhibit high light transmittance and flexibility. Therefore, they can be used for next-generation flexible and transparent semiconductor devices.”
Journal Reference:
Jang. J, et al. (2022) Fermi-Level Pinning-Free WSe2 Transistors via 2D Van der Waals Metal Contacts and Their Circuits. Advanced Materials doi:10.1002/adma.202109899