HTD (Hydrogen terminated diamond) is a candidate topological Mott material. The ARPES measurements on HTD were done with low energy resolution of 100 meV and could not resolve a possible Dirac cone for which higher resolution ARPES measurements at low temperatures are needed in the future. Diamond is an insulator in the bulk and has both metal and insulator phases on HTD surface. Moreover, since the metal phase on the HTD surface comes from the Mott IMT, HTD is interpreted as an inhomogeneous, topological Mott material.
This is early lab work that needs more confirmation, improvement and then scaling.
In conclusion, researchers found that the local metal phase induced by the Mott IMT in HTD reduces resistance of channel in the HTD-based transistor. Finally, the local metal phase leads to high carrier and current densities in the transistor—the Mott transistor that can be used in the following applications: neuromorphic device for neuromorphic computing, RF power amplifier over 10 GHz power transistor with high current, and in devices for non-Boolean computing.
A limitation of semiconductor transistors using semiconductor characteristics is the high power and heat dissipated due to high on-resistance in the electrically conducting channel. Past attempts have been made to reduce the resistance of the channel, such as the Mott transistor utilizing metallic character. However, the Mott insulator VO2-based transistor does not cause high gating effect due to large leakage current. Although GaN semiconductor-based power transistors are used for high power applications, their performance is limited by the high heat dissipation.
Diamond is an ultra-wide bandgap semiconductor with very attractive electrical, thermal, and mechanical characteristics. In particular, there has been significant progress in the synthesis of hole-doped diamond using boron as the dopant element, but challenges remain, especially the detrimental effect on crystallinity arising from high boron concentrations. Hydrogen termination of diamond surfaces is an attractive alternative that leads to hole (or p-type) conductivity enabled by adsorbates molecules from air or by a layer of a metal oxide. The adsorbate molecules or the metal oxide layer on hydrogen-terminated diamond (HTD) surface act as high electron affinity materials and lead to the formation of a quasi-two-dimensional hole gas confined near the HTD surface via the phenomenon of surface transfer doping. This has enhanced diamond’s potential for electronics applications, especially with regard to high-current and high-power transistors.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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I am very sceptic about how they keep the hydrogen not leaving the stage. Especially when the temperature rises.
There is no material what can keep hydrogen molecules back.
The hydrogen is chemically bound to the surface of the diamond: When you cleave diamond, you get a dense array of dangling bonds that aren’t terribly stable, they tend to latch onto anything present. Oxygen or hydrogen, usually. “HTD” is diamond with all the dangling bonds tied up by hydrogen.
Think of it as a really high molecular weight hydrocarbon.
Can someone explain this to me as if I’m a person who has had too much New Year’s Eve feasting, wine and scotch?
Scratch that—explain it to me like I’m 7 years old and not sure why I should be interested but suspect that I should be.
My takeaway is that this material can potentially make logic gates in circuits more efficient than silicon.
I know, right? Not even a breakdown of the acronyms.
Yeah, I’m not sure how anybody who has never taken a class in transistor design, or read a lot of papers on this stuff would ever follow it. That’s what happens when you cut and past from technical papers on a site for laymen.
“Mott” materials are materials that have lots of conduction band electrons, you’d expect them to exhibit metallic conduction, but because of some quirk about how the electrons interact with each other, they’re not mobile, so you get an insulator, instead.
Because you do have a lot of conduction band electrons, if you can locally and reversibly interfere with that quirk, you can get the material to switch between insulator and metallic conductor, and back again.
This results in better switching than in semi-conductor type transistors, because they only switch between a very high resistance and moderate resistance state, while the Mott materials switch between very high resistance and very low resistance.
In this case, the Mott material is just the surface of the diamond, where the dangling bonds are terminated with hydrogen. Normally diamond would be a semiconductor, but they’ve found a way to flood it locally with enough electrons to get metallic behavior instead.
So you have a transistor with a very high ratio of on to off conductivity, and because it’s diamond, it’s very heat resistant, and conducts away heat very rapidly.
So, a really good transistor hiding behind all those acronyms.
Brett, this is one of the clearest explanations I’ve seen in some time. Thanks.
This article discusses how to make low power high speed transistors. Think CPUs that start at 10GHz while using less power than current CPUs.