Tech
Room-temperature terahertz device opens door to 6G networks
In a world first, researchers at Nagoya University in Japan have successfully developed a resonant tunnel diode (RTD) that operates at room temperature made entirely from Group IV semiconductor materials.
The development of an RTD that operates at room temperature means the device could be deployed at scale for next-generation wireless communication systems. The use of only non-toxic Group IV semiconductor materials also supports more sustainable manufacturing processes.
This research marks a pivotal step toward terahertz wireless components that deliver unprecedented speed and data handling capacity with superior energy efficiency.
“Compared to InGaAs-based Group III-V RTDs that include toxic and rare elements, such as indium and arsenic, Group IV compounds-based RTDs are safer, lower cost, and offer advantages for creating integrated production processes,” said senior author Dr. Shigehisa Shibayama from the Nagoya University Graduate School of Engineering.
The results are published in the journal ACS Applied Electronic Materials.
Terahertz waves and quantum devices
Researchers have long struggled to achieve the high-speed and large-volume data transfer needed for sixth-generation (6G) cellular networks.
One promising solution is wireless communication using terahertz waves—electromagnetic waves that vibrate a trillion times per second, enabling ultra-high-speed data transmission. However, many technical challenges remain before this technology can be made practical for consumer applications.
A critical component for realizing terahertz communication is the RTD. This quantum device operates through negative differential resistance, a counterintuitive property where increasing voltage actually decreases current. When part of a properly designed circuit, this property allows the diodes to sustain high-frequency oscillations that would otherwise decay due to electrical losses.
Moving beyond laboratory constraints
The secret behind an RTD lies in its double-barrier structure, where electrons or holes tunnel through layers of different semiconductor materials, each only a few atoms thick. These layers have mainly been created from InGaAs-based Group III-V materials that include toxic and rare elements, such as indium and arsenic.
In previous research by the same group, the researchers created a p-type RTD using only Group IV materials, specifically germanium-tin (GeSn) and germanium-silicon-tin (GeSiSn) alloys. One limitation was that the diode only functioned at extremely low temperatures, around -263°C. Since consumer electronics and wireless systems cannot practically reach this level of cooling, the device would have remained a laboratory curiosity.
Shibayama and his colleagues have now discovered how to use only Group IV materials to produce a p-RTD that functions at room temperatures of around 27°C. This significant improvement opens new possibilities for the widespread adoption of terahertz semiconductor devices.
The research group achieved its breakthrough by introducing hydrogen gas during the layer formation process. They tested three different scenarios:
- introducing hydrogen gas to both the two GeSiSn layers and three GeSn layers
- introducing no hydrogen gas
- introducing hydrogen gas to only the three GeSn layers.
In the last scenario, hydrogen gas restricted island growth and mixing between layers, resulting in a smooth and well-ordered double-barrier structure.
“The RTD cannot function if these layers are mixed,” said Dr. Shibayama.
“If there are defects in the layers, electrons can tunnel through these easier routes, leading to current leakage. This leakage current needs to be reduced for negative differential resistance—the key property of an RTD—to occur.”
More information:
Shota Torimoto et al, Room-Temperature Operation of Ge1–xSnx/Ge1–x–ySixSny Resonant Tunneling Diodes Featured with H2 Introduction during Molecular Beam Epitaxy. ACS Applied Electronic Materials (2025). DOI: 10.1021/acsaelm.5c01049
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The US Food and Drug Administration today approved a pill version of the blockbuster anti-obesity drug Wegovy. Made by Novo Nordisk, the pill is taken once a day. The company’s original version of Wegovy is a weekly injection. Both drugs contain the same active ingredient, semaglutide.
“This allows patients with obesity who want to lose weight to have a choice between a once weekly injection or a daily tablet,” says Martin Holst Lange, chief scientific officer at Novo Nordisk.
With the soaring popularity of injectable GLP-1 drugs for weight loss, Novo Nordisk and other pharmaceutical companies have been racing to make effective pill versions that could be preferable for some patients. These drugs mimic a naturally occurring hormone in the body that acts on the brain and gut to promote a feeling of fullness.
In clinical trial results published in the New England Journal of Medicine, participants who took the pill achieved an average weight loss of 13.6 percent by 64 weeks. Nearly 30 percent of people lost 20 percent or more of their weight. The study also showed improvements in cardiovascular disease risk and physical activity levels similar to the injectable version.
While pills can sometimes be a more convenient option, patients may not always take them as prescribed, making them less effective. The clinical trial investigators estimated that in an ideal scenario where participants take the pill every day as prescribed, weight loss would be 16.6 percent—which is similar to results seen with injectable Wegovy.
Novo Nordisk first won approval for an oral semaglutide, sold under the brand name Rybelsus, in 2019 to treat type 2 diabetes. That drug has never been approved for obesity and is not as effective for weight loss as newer GLP-1 medications. The Wegovy pill is essentially a higher-dose version of Rybselsus.
“The efficacy for the obesity pill at the end of the day is driven by dose. Higher doses are required to achieve full weight-loss potential for obesity,” Lange says. The Wegovy pill is 25 milligrams while Rybelsus is 14 milligrams.
The most common side effects of oral Wegovy include nausea and vomiting, which are also side effects of the injectable version.
Novo has not disclosed the exact timeline for the drug’s launch, but Lange says it will be available sometime in the first few months of 2026. Production of the medication is already underway at Novo Nordisk’s US manufacturing sites, and the company expects to have enough of the drug to meet US demand.
The first thing to think about is how you’re going to drain the water from the dehumidifier. In the basement, the best thing you can do is to use the dehumidifier’s continuous water drain tube to either the sump pump or a drain. If those options are not available, you might be emptying the tank multiple times a day. The first time I put a dehumidifier in the basement, the tank was filled in three hours’ time. It’s all about the drainage. Also, knowing how to read a label. If you have a 50-pint humdidifier that means the appliance can remove 50 pints of moisture from the air in a 24-hour period; it’s not the internal tank capacity. Also, look for the maximum area coverage. For example, the Honeywell Smart 50 pint can remove 50 pints of water from 4,000 sq ft—the size of a whole house—in 24 hours.
If you, like me, also need a dehumidifier in your city apartment, then consider buying one that’s easy to move around with wheels and a handle. Some of these machines are heavy. Also, a small dehumidifier in the bathroom is a good idea to keep the dampness at bay, especially if you have mold growing on your grout.
Lastly, do not drink the water collected in your dehumidifier tank. That water is not potable. Pour it down the drain. A dehumidifier is not creating distilled water; that’s a different process and appliance.
Over the weekend, the Justice Department released three new data sets comprising files related to Jeffrey Epstein. The DOJ had previously released nearly 4,000 documents prior to the Friday midnight deadline required by the Epstein Files Transparency Act.
As with Friday’s release, the new tranche appears to contain hundreds of photographs, along with various court records pertaining to Epstein and his associates. The first of the additional datasets, Data Set 5, is photos of hard drives and physical folders, as well as chain-of-custody forms. Data Set 6 appears to mostly be grand jury materials from cases out of the Southern District of New York against Epstein and his coconspirator, Ghislaine Maxwell. Data Set 7 includes more grand jury materials from those cases, as well as materials from a separate 2007 Florida grand jury.
Data Set 7 also includes an out-of-order transcript between R. Alexander Acosta and the DOJ’s Office of Professional Responsibility from 2019. According to the transcript, the OPR was investigating whether attorneys in the Southern District of Florida US Attorney’s Office committed professional misconduct by entering into a non-prosecution agreement with Epstein, who was being investigated by state law enforcement on sexual battery charges. Acosta was the head of the office when the agreement was signed.
Leading up to the deadline to release materials, the DOJ made three separate requests to unseal grand jury materials. Those requests were granted earlier this month.
The initial release of the Epstein files was met with protest, particularly by Epstein victims and Democratic lawmakers. “The public received a fraction of the files, and what we received was riddled with abnormal and extreme redactions with no explanation,” wrote a group of 19 women who had survived abuse from Epstein and Maxwell in a statement posted on social media. Senator Chuck Schumer said Monday that he would force a vote that would allow the Senate to sue the Trump administration for a full release of the Epstein files.
Along with the release of the new batch of files over the weekend, the Justice Department also removed at least 16 files from its initial offering, including a photograph that depicted Donald Trump. The DOJ later restored that photograph, saying in a statement on X that it had initially been flagged “for potential further action to protect victims.” The post went on to say that “after the review, it was determined there is no evidence that any Epstein victims are depicted in the photograph, and it has been reposted without any alteration or redaction.”
The Justice Department acknowledged in a fact sheet on Sunday that it has “hundreds of thousands of pages of material to release,” claiming that it has more than 200 lawyers reviewing files prior to release.
Wegovy pill approved by US FDA for weight loss
FDA approves first GLP-1 pill for obesity from Wegovy maker Novo Nordisk
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