Cadmium Zinc Telluride: The wonder material powering a medical 'revolution'

This isn't much more than a factoid, but notice that many of the useful semiconductors are made from elements that straddle the column containing silicon and germanium. Making compounds whose outer shell electrons add up to be silicon-like lets you make semiconductors, but with electrical and optical properties that you can tune. GaAs is another one, and the LED's are made by choosing particular combinations that have specific bandgap energies corresponding to colors of photons.

Part of the "magic" involves finding ratios of elements that have relatively little mechanical strain, because the atoms "fit" just right, which introduce defects that degrade the semiconductor behavior.

Probably not related

https://en.wikipedia.org/wiki/Gamma-ray_laser

Huh, I worked on a CZT radiation detector in undergrad back in 2007.

A few years ago, CZT detectors made by eV Products showed up in quantity on eBay. Pretty much everyone interested in radioactivity seemed to snap one up back then. It took a fairly long time for folks to figure out how to use them well! But they're really not bad, especially for the size.

Here's some spectra with 3% FWHM @ 662 keV:

https://maximus.energy/index.php/2020/05/01/gamma-spectrosco...

You mean they’re good because the measurements are precise?

FYI "factoid" means it's an incorrect piece of information passed off as a fact.

FYI, what you said is one meaning. But it is also, surprisingly, defined as brief trivial fact.

Nowadays it also refers to trivial facts: https://www.merriam-webster.com/dictionary/factoid

> pulmonary embolism

Ahh

In fact, your comment is a factoid (in your meaning or the other replies' interpretation)

Factoids are facts without citation, I suppose the other factoid to be mentioned is the direct band gap (which CZT has?)

https://en.wikipedia.org/wiki/Direct_and_indirect_band_gaps

For those unfamiliar with this, when a semiconductor has a direct band gap that means that it is likely to be suitable for devices that emit or detect photons, because when photons are absorbed, they generate electron-hole pairs, and when electron-hole pairs combine, their energy is released as photons.

In semiconductors with indirect band gap, when electron-hole pairs combine they usually just heat the material, instead of emitting light, which is why silicon, for instance, is not suitable for making LEDs.

While a direct band gap is desirable in LEDs, lasers and photodetectors, an indirect band gap is preferable in other applications where you do not want electrons and holes to recombine easily, e.g. in bipolar transistors or SCRs and in many kinds of diodes.

The article says that the use of CZT is not new, but now the material has become much more affordable, due to improved production techniques, which has opened up a lot of application fields for it, which were previously prevented by its scarcity and cost.

There are plenty of materials that have been known for a long time to be better than those normally used in certain applications, but which still do not replace the inferior alternatives due to excessive cost, so discovering any new process that can make them cheaply is as important as knowing the properties of the material.