Worms metabolize quantum dots. Huh?

Factual Questions
1

Subject says it all. Money grafs:

In the experiment the scientists spiked soil with cadmium chloride and sodium tellurite (sodium, telluride and oxygen). The ability of worms to process cadmium is well known, but it wasn’t clear what they would do with the tellurium in the sodium tellurite.

The worms ended up making tiny particles of cadmium telluride, a crystalline compound that is also a semiconductor. Those tiny particles — called quantum dots — were then taken out of the worms’ tissue. The dots themselves are only nanometers across.

Anyone tell me more about quantum dots and what they have to with quanta coming out of a worm’s guts?*

*Just thought of this. No harm in long quote, right?

KING CLAUDIUS: Now, Hamlet, where’s Polonius?

HAMLET: At supper.

KING CLAUDIUS: At supper! where?

HAMLET: Not where he eats, but where he is eaten: a certain
convocation of politic worms are e’en at him. Your
worm is your only emperor for diet: we fat all
creatures else to fat us, and we fat ourselves for
maggots: your fat king and your lean beggar is but
variable service, two dishes, but to one table:
that’s the end.

KING CLAUDIUS: Alas, alas!

HAMLET: A man may fish with the worm that hath eat of a
king, and cat of the fish that hath fed of that worm.

KING CLAUDIUS: What dost you mean by this?

HAMLET: Nothing but to show you how a king may go a
progress through the guts of a beggar.

2

As it says in the article, a quantum dot is a very small semiconductor crystal. Because it’s a “dot” and not a film, it’s constrained in three dimensions, leading to some interesting and useful effects. The crystals grown in the worms are not of good quality; this is a “let’s see if we can do it” experiment, not a production technique.

3

I’m not sure, but I think a dot confines something like a photon or electron to a single energy band/quanta. It has to have exactly that energy to enter the dot. Anything above or below and the dot is essentially impermeable.

However I wonder how that would work in conjunction with the phenomenon of tunneling - or how you would ever even test that.

4

No sweat. Worms are great at tunnelling too.

5

Actually, I looked up quantum dot in wiki and it was incomprehensible as usual but I did search on tunneling while I was there and found this, which was a little embarrassing.

It’s in the section on fabrication.

It’s embarrassing because if I had just thought for a moment about what tunneling actually means, I would have realized that in that context, there are no impermeable barriers.

6

In truth “quantum dot” is really just an exciting term for small, 3-dimensional clusters of atoms. Specifically, a quantum dot is just a type of nanoparticle that is made up of semiconducting materials. QDs are very interesting because they behave like artificial atoms. In atoms, electrons can only occupy discrete orbitals; this effect accounts for the different colors emitted or absorbed by atoms when electrons hop between energy levels.

Due to their small size (which is constrained in all 3 dimensions) and semiconducting behavior, QDs behave like artificial atoms. They have the same type of discrete energy levels. The most exciting aspect of QDs is that by controlling the size and structure of the QD, one could tune the fluorescent emission properties of the particle. Want something that behaves like an atom and emits light at exactly 520 nm? A QD could be synthesized to do just that.

There are lots of ways to make these things, and it is pretty cool that worms can process stray telluride ions into QDs!

7

Borg worms!