New method gets better performance out of atomically thin transistors
Atomically thin transistors are the key to unlocking better performance in a variety of electronic devices. A new method developed by a team of researchers from Harvard University and the Massachusetts Institute of Technology (MIT) promises to get even better performance out of these devices by using 2D materials.
The team’s approach is based on a principle called quantum tunneling. This phenomenon occurs when an electron is able to pass through a barrier that it would normally be unable to surmount. By harnessing this effect, the team was able to create a transistor that can switch between two conducting states with very little power consumption.
The researchers fabried their transistor out of molybdenum disulfide (MoS2), a two-dimensional material that is just one atom thick. They used a technique called atomic layer deposition to create a very thin film of MoS2 on a silicon wafer.
To create the transistor, the team first deposited a layer of MoS2 just one atom thick onto the silicon wafer. They then used a laser to pattern this layer into a series of nanoscopic wires.
The next step was to deposit another layer of MoS2 onto the wires. This second layer was also just one atom thick. However, the team used a different deposition technique that resulted in a slightly different atomic structure.
As a result of this different atomic structure, the MoS2 wires in the second layer were slightly wider than the wires in the first layer. This width difference created a “quantum tunneling barrier” between the two layers of wires.
The team placed a gold electrode at either end of the MoS2 wires. When a voltage was applied to the electrodes, the electrons in the MoS2 wires were able to tunnel through the barrier between the two layers of wires.
This quantum tunneling effect allowed the transistor to switch between two conducting states with very little power consumption. In one state, the MoS2 wires were able to conduct electricity, and in the other state, they were not.
The team’s approach is a significant advance over previous approaches to creating atomically thin transistors. In particular, it is much easier to fabriate transistors using the team’s approach.
The team’s approach also has the potential to be used in a variety of other devices, such as sensors and solar cells.
The study was published in the journal Nature Nanotechnology.