HAVE you ever wondered what makes your iPhone touchscreen so touchy?

Well, it's called indium tin oxide and according to some reports, it's running out.

A new article by New Scientist reporter James Mitchell Crow claims that the world's reserves of indium may only last another decade.

Indium, most commonly found in zinc deposits, is used to create indium tin oxide, or ITO.

ITO, in turn, is one of the key materials for the production of touch and LED screens. It's see-through but also conducts electricity.

Crow quoted figures from the US Geological Survey that put the amount of indium reserves in the world at about 16,000 tonnes.

"Dividing that by the rate at which we are currently using the stuff suggests those reserves will be exhausted by 2020," he said.

It's no surprise then that the race is on for the consumer electronics industry to find some more indium — or an adequate replacement.

According to Gartner analyst Dean Freeman, the most likely replacement for ITO will be carbon nanotubes, or CNT.

But that technology isn't quite ready yet.

"I think they're still a few years away from perfecting carbon nanotubes in that application, but they're getting much, much closer," he told news.com.au.

"If you start to see additional shortages of indium tin oxide, you might see it happen sooner than later."

One of the challenges of CNT technology is in refining the material to ensure its consistency.

"Where you start to get a higher cost associated with it is in the purification steps, trying to get similar electrical characteristics, trying to get them approximately to the same size," said Mr Freeman.

"That's been one of the issues why we haven't seen carbon nanotubes really take over in many electrical applications.

"We're still learning how to purify it and get it to the point where we have a consistent material day in, day out."

In the meantime, Mr Freeman said the industry was looking at ways to make the existing reserves of indium last longer.

"Any time we get into a situation like this, at least in the electronics industry, you see multiple paths looking to resolve the problem," he said.

"So we're also figuring out how we can use less indium tin oxide. You know — thinner layers, stretch it out further and so on."

Let's hope they can stretch it far enough.